diff --git a/netmap/context.go b/netmap/context.go
index e1c426a..00942e5 100644
--- a/netmap/context.go
+++ b/netmap/context.go
@@ -35,6 +35,11 @@ type context struct {
 
 	// container backup factor
 	cbf uint32
+
+	// nodes already used in previous selections, which is needed when the placement
+	// policy uses the UNIQUE flag. Nodes marked as used are not used in subsequent
+	// base selections.
+	usedNodes map[uint64]bool
 }
 
 // Various validation errors.
@@ -58,6 +63,7 @@ func newContext(nm NetMap) *context {
 
 		numCache:   make(map[string]uint64),
 		weightFunc: defaultWeightFunc(nm.nodes),
+		usedNodes:  make(map[uint64]bool),
 	}
 }
 
@@ -76,6 +82,12 @@ func (c *context) setCBF(cbf uint32) {
 	}
 }
 
+func (c *context) addUsedNodes(ns ...NodeInfo) {
+	for _, n := range ns {
+		c.usedNodes[n.hash] = true
+	}
+}
+
 func defaultWeightFunc(ns nodes) weightFunc {
 	mean := newMeanAgg()
 	min := newMinAgg()
diff --git a/netmap/netmap.go b/netmap/netmap.go
index c839df8..c9969b6 100644
--- a/netmap/netmap.go
+++ b/netmap/netmap.go
@@ -181,6 +181,10 @@ func (m NetMap) ContainerNodes(p PlacementPolicy, pivot []byte) ([][]NodeInfo, e
 
 	result := make([][]NodeInfo, len(p.replicas))
 
+	// Note that the cached selectors are not used when the policy contains the UNIQUE flag.
+	// This is necessary because each selection vector affects potentially the subsequent vectors
+	// and thus we call getSelection in such case, in order to take into account nodes previously
+	// marked as used by earlier replicas.
 	for i := range p.replicas {
 		sName := p.replicas[i].GetSelector()
 		if sName == "" {
@@ -198,18 +202,39 @@ func (m NetMap) ContainerNodes(p PlacementPolicy, pivot []byte) ([][]NodeInfo, e
 			}
 
 			for i := range p.selectors {
-				result[i] = append(result[i], flattenNodes(c.selections[p.selectors[i].GetName()])...)
+				if p.unique {
+					nodes, err := c.getSelection(p.selectors[i])
+					if err != nil {
+						return nil, err
+					}
+					result[i] = append(result[i], flattenNodes(nodes)...)
+				} else {
+					result[i] = append(result[i], flattenNodes(c.selections[p.selectors[i].GetName()])...)
+				}
+			}
+
+			if p.unique {
+				c.addUsedNodes(result[i]...)
 			}
 
 			continue
 		}
 
-		nodes, ok := c.selections[sName]
-		if !ok {
-			return nil, fmt.Errorf("selector not found: REPLICA '%s'", sName)
+		if p.unique {
+			nodes, err := c.getSelection(*c.processedSelectors[sName])
+			if err != nil {
+				return nil, err
+			}
+			result[i] = append(result[i], flattenNodes(nodes)...)
+			c.addUsedNodes(result[i]...)
+		} else {
+			nodes, ok := c.selections[sName]
+			if !ok {
+				return nil, fmt.Errorf("selector not found: REPLICA '%s'", sName)
+			}
+			result[i] = append(result[i], flattenNodes(nodes)...)
 		}
 
-		result[i] = append(result[i], flattenNodes(nodes)...)
 	}
 
 	return result, nil
diff --git a/netmap/parser/Query.g4 b/netmap/parser/Query.g4
index a52746a..abae181 100644
--- a/netmap/parser/Query.g4
+++ b/netmap/parser/Query.g4
@@ -4,7 +4,7 @@ options {
     tokenVocab = QueryLexer;
 }
 
-policy: repStmt+ cbfStmt? selectStmt* filterStmt* EOF;
+policy: UNIQUE? repStmt+ cbfStmt? selectStmt* filterStmt* EOF;
 
 repStmt:
     REP Count = NUMBER1     // number of object replicas
diff --git a/netmap/parser/Query.interp b/netmap/parser/Query.interp
index 60db0a9..df98c28 100644
Binary files a/netmap/parser/Query.interp and b/netmap/parser/Query.interp differ
diff --git a/netmap/parser/Query.tokens b/netmap/parser/Query.tokens
index 8fdec7d..6376ea2 100644
Binary files a/netmap/parser/Query.tokens and b/netmap/parser/Query.tokens differ
diff --git a/netmap/parser/QueryLexer.g4 b/netmap/parser/QueryLexer.g4
index f32023c..c9b5ae6 100644
--- a/netmap/parser/QueryLexer.g4
+++ b/netmap/parser/QueryLexer.g4
@@ -5,6 +5,7 @@ AND_OP     : 'AND';
 OR_OP      : 'OR';
 SIMPLE_OP  : 'EQ' | 'NE' | 'GE' | 'GT' | 'LT' | 'LE';
 
+UNIQUE   : 'UNIQUE';
 REP      : 'REP';
 IN       : 'IN';
 AS       : 'AS';
diff --git a/netmap/parser/QueryLexer.interp b/netmap/parser/QueryLexer.interp
index 71b093c..95db144 100644
Binary files a/netmap/parser/QueryLexer.interp and b/netmap/parser/QueryLexer.interp differ
diff --git a/netmap/parser/QueryLexer.tokens b/netmap/parser/QueryLexer.tokens
index 8fdec7d..6376ea2 100644
Binary files a/netmap/parser/QueryLexer.tokens and b/netmap/parser/QueryLexer.tokens differ
diff --git a/netmap/parser/generate.go b/netmap/parser/generate.go
index f2202d2..66a855b 100644
--- a/netmap/parser/generate.go
+++ b/netmap/parser/generate.go
@@ -1,4 +1,4 @@
 package parser
 
-// ANTLR can be downloaded from https://www.antlr.org/download/antlr-4.12.0-complete.jar
-//go:generate java -Xmx500M -cp "./antlr-4.12.0-complete.jar:$CLASSPATH" org.antlr.v4.Tool -Dlanguage=Go -no-listener -visitor QueryLexer.g4 Query.g4
+// ANTLR can be downloaded from https://www.antlr.org/download/antlr-4.13.0-complete.jar
+//go:generate java -Xmx500M -cp "./antlr-4.13.0-complete.jar:$CLASSPATH" org.antlr.v4.Tool -Dlanguage=Go -no-listener -visitor QueryLexer.g4 Query.g4
diff --git a/netmap/parser/query_base_visitor.go b/netmap/parser/query_base_visitor.go
index fa1cce8..4badbce 100644
--- a/netmap/parser/query_base_visitor.go
+++ b/netmap/parser/query_base_visitor.go
@@ -1,3 +1,5 @@
+// Code generated from Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
+
 package parser // Query
 
 import "github.com/antlr4-go/antlr/v4"
diff --git a/netmap/parser/query_lexer.go b/netmap/parser/query_lexer.go
index b9224b6..c1ae141 100644
--- a/netmap/parser/query_lexer.go
+++ b/netmap/parser/query_lexer.go
@@ -1,11 +1,12 @@
+// Code generated from QueryLexer.g4 by ANTLR 4.13.0. DO NOT EDIT.
+
 package parser
 
 import (
 	"fmt"
+	"github.com/antlr4-go/antlr/v4"
 	"sync"
 	"unicode"
-
-	"github.com/antlr4-go/antlr/v4"
 )
 
 // Suppress unused import error
@@ -42,114 +43,119 @@ func querylexerLexerInit() {
 		"DEFAULT_MODE",
 	}
 	staticData.LiteralNames = []string{
-		"", "'NOT'", "'AND'", "'OR'", "", "'REP'", "'IN'", "'AS'", "'CBF'",
-		"'SELECT'", "'FROM'", "'FILTER'", "'*'", "'SAME'", "'DISTINCT'", "'('",
-		"')'", "'@'", "", "", "'0'",
+		"", "'NOT'", "'AND'", "'OR'", "", "'UNIQUE'", "'REP'", "'IN'", "'AS'",
+		"'CBF'", "'SELECT'", "'FROM'", "'FILTER'", "'*'", "'SAME'", "'DISTINCT'",
+		"'('", "')'", "'@'", "", "", "'0'",
 	}
 	staticData.SymbolicNames = []string{
-		"", "NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "REP", "IN", "AS", "CBF",
-		"SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME", "CLAUSE_DISTINCT",
-		"L_PAREN", "R_PAREN", "AT", "IDENT", "NUMBER1", "ZERO", "STRING", "WS",
+		"", "NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "IN",
+		"AS", "CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME",
+		"CLAUSE_DISTINCT", "L_PAREN", "R_PAREN", "AT", "IDENT", "NUMBER1", "ZERO",
+		"STRING", "WS",
 	}
 	staticData.RuleNames = []string{
-		"NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "REP", "IN", "AS", "CBF",
-		"SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME", "CLAUSE_DISTINCT",
+		"NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "IN", "AS",
+		"CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME", "CLAUSE_DISTINCT",
 		"L_PAREN", "R_PAREN", "AT", "IDENT", "Digit", "Nondigit", "NUMBER1",
 		"ZERO", "STRING", "ESC", "UNICODE", "HEX", "SAFECODEPOINTSINGLE", "SAFECODEPOINTDOUBLE",
 		"WS",
 	}
 	staticData.PredictionContextCache = antlr.NewPredictionContextCache()
 	staticData.serializedATN = []int32{
-		4, 0, 22, 204, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2,
+		4, 0, 23, 213, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2,
 		4, 7, 4, 2, 5, 7, 5, 2, 6, 7, 6, 2, 7, 7, 7, 2, 8, 7, 8, 2, 9, 7, 9, 2,
 		10, 7, 10, 2, 11, 7, 11, 2, 12, 7, 12, 2, 13, 7, 13, 2, 14, 7, 14, 2, 15,
 		7, 15, 2, 16, 7, 16, 2, 17, 7, 17, 2, 18, 7, 18, 2, 19, 7, 19, 2, 20, 7,
 		20, 2, 21, 7, 21, 2, 22, 7, 22, 2, 23, 7, 23, 2, 24, 7, 24, 2, 25, 7, 25,
-		2, 26, 7, 26, 2, 27, 7, 27, 2, 28, 7, 28, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3,
-		1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 3, 3, 83, 8, 3, 1, 4, 1, 4, 1, 4, 1,
-		4, 1, 5, 1, 5, 1, 5, 1, 6, 1, 6, 1, 6, 1, 7, 1, 7, 1, 7, 1, 7, 1, 8, 1,
-		8, 1, 8, 1, 8, 1, 8, 1, 8, 1, 8, 1, 9, 1, 9, 1, 9, 1, 9, 1, 9, 1, 10, 1,
-		10, 1, 10, 1, 10, 1, 10, 1, 10, 1, 10, 1, 11, 1, 11, 1, 12, 1, 12, 1, 12,
-		1, 12, 1, 12, 1, 13, 1, 13, 1, 13, 1, 13, 1, 13, 1, 13, 1, 13, 1, 13, 1,
-		13, 1, 14, 1, 14, 1, 15, 1, 15, 1, 16, 1, 16, 1, 17, 1, 17, 1, 17, 5, 17,
-		143, 8, 17, 10, 17, 12, 17, 146, 9, 17, 1, 18, 1, 18, 1, 19, 1, 19, 1,
-		20, 1, 20, 5, 20, 154, 8, 20, 10, 20, 12, 20, 157, 9, 20, 1, 21, 1, 21,
-		1, 22, 1, 22, 1, 22, 5, 22, 164, 8, 22, 10, 22, 12, 22, 167, 9, 22, 1,
-		22, 1, 22, 1, 22, 1, 22, 5, 22, 173, 8, 22, 10, 22, 12, 22, 176, 9, 22,
-		1, 22, 3, 22, 179, 8, 22, 1, 23, 1, 23, 1, 23, 3, 23, 184, 8, 23, 1, 24,
-		1, 24, 1, 24, 1, 24, 1, 24, 1, 24, 1, 25, 1, 25, 1, 26, 1, 26, 1, 27, 1,
-		27, 1, 28, 4, 28, 199, 8, 28, 11, 28, 12, 28, 200, 1, 28, 1, 28, 0, 0,
-		29, 1, 1, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 15, 8, 17, 9, 19, 10, 21,
-		11, 23, 12, 25, 13, 27, 14, 29, 15, 31, 16, 33, 17, 35, 18, 37, 0, 39,
-		0, 41, 19, 43, 20, 45, 21, 47, 0, 49, 0, 51, 0, 53, 0, 55, 0, 57, 22, 1,
-		0, 8, 1, 0, 48, 57, 3, 0, 65, 90, 95, 95, 97, 122, 1, 0, 49, 57, 9, 0,
-		34, 34, 39, 39, 47, 47, 92, 92, 98, 98, 102, 102, 110, 110, 114, 114, 116,
-		116, 3, 0, 48, 57, 65, 70, 97, 102, 3, 0, 0, 31, 39, 39, 92, 92, 3, 0,
-		0, 31, 34, 34, 92, 92, 3, 0, 9, 10, 13, 13, 32, 32, 211, 0, 1, 1, 0, 0,
-		0, 0, 3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9, 1, 0, 0,
-		0, 0, 11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 0, 15, 1, 0, 0, 0, 0, 17, 1, 0,
-		0, 0, 0, 19, 1, 0, 0, 0, 0, 21, 1, 0, 0, 0, 0, 23, 1, 0, 0, 0, 0, 25, 1,
-		0, 0, 0, 0, 27, 1, 0, 0, 0, 0, 29, 1, 0, 0, 0, 0, 31, 1, 0, 0, 0, 0, 33,
-		1, 0, 0, 0, 0, 35, 1, 0, 0, 0, 0, 41, 1, 0, 0, 0, 0, 43, 1, 0, 0, 0, 0,
-		45, 1, 0, 0, 0, 0, 57, 1, 0, 0, 0, 1, 59, 1, 0, 0, 0, 3, 63, 1, 0, 0, 0,
-		5, 67, 1, 0, 0, 0, 7, 82, 1, 0, 0, 0, 9, 84, 1, 0, 0, 0, 11, 88, 1, 0,
-		0, 0, 13, 91, 1, 0, 0, 0, 15, 94, 1, 0, 0, 0, 17, 98, 1, 0, 0, 0, 19, 105,
-		1, 0, 0, 0, 21, 110, 1, 0, 0, 0, 23, 117, 1, 0, 0, 0, 25, 119, 1, 0, 0,
-		0, 27, 124, 1, 0, 0, 0, 29, 133, 1, 0, 0, 0, 31, 135, 1, 0, 0, 0, 33, 137,
-		1, 0, 0, 0, 35, 139, 1, 0, 0, 0, 37, 147, 1, 0, 0, 0, 39, 149, 1, 0, 0,
-		0, 41, 151, 1, 0, 0, 0, 43, 158, 1, 0, 0, 0, 45, 178, 1, 0, 0, 0, 47, 180,
-		1, 0, 0, 0, 49, 185, 1, 0, 0, 0, 51, 191, 1, 0, 0, 0, 53, 193, 1, 0, 0,
-		0, 55, 195, 1, 0, 0, 0, 57, 198, 1, 0, 0, 0, 59, 60, 5, 78, 0, 0, 60, 61,
-		5, 79, 0, 0, 61, 62, 5, 84, 0, 0, 62, 2, 1, 0, 0, 0, 63, 64, 5, 65, 0,
-		0, 64, 65, 5, 78, 0, 0, 65, 66, 5, 68, 0, 0, 66, 4, 1, 0, 0, 0, 67, 68,
-		5, 79, 0, 0, 68, 69, 5, 82, 0, 0, 69, 6, 1, 0, 0, 0, 70, 71, 5, 69, 0,
-		0, 71, 83, 5, 81, 0, 0, 72, 73, 5, 78, 0, 0, 73, 83, 5, 69, 0, 0, 74, 75,
-		5, 71, 0, 0, 75, 83, 5, 69, 0, 0, 76, 77, 5, 71, 0, 0, 77, 83, 5, 84, 0,
-		0, 78, 79, 5, 76, 0, 0, 79, 83, 5, 84, 0, 0, 80, 81, 5, 76, 0, 0, 81, 83,
-		5, 69, 0, 0, 82, 70, 1, 0, 0, 0, 82, 72, 1, 0, 0, 0, 82, 74, 1, 0, 0, 0,
-		82, 76, 1, 0, 0, 0, 82, 78, 1, 0, 0, 0, 82, 80, 1, 0, 0, 0, 83, 8, 1, 0,
-		0, 0, 84, 85, 5, 82, 0, 0, 85, 86, 5, 69, 0, 0, 86, 87, 5, 80, 0, 0, 87,
-		10, 1, 0, 0, 0, 88, 89, 5, 73, 0, 0, 89, 90, 5, 78, 0, 0, 90, 12, 1, 0,
-		0, 0, 91, 92, 5, 65, 0, 0, 92, 93, 5, 83, 0, 0, 93, 14, 1, 0, 0, 0, 94,
-		95, 5, 67, 0, 0, 95, 96, 5, 66, 0, 0, 96, 97, 5, 70, 0, 0, 97, 16, 1, 0,
-		0, 0, 98, 99, 5, 83, 0, 0, 99, 100, 5, 69, 0, 0, 100, 101, 5, 76, 0, 0,
-		101, 102, 5, 69, 0, 0, 102, 103, 5, 67, 0, 0, 103, 104, 5, 84, 0, 0, 104,
-		18, 1, 0, 0, 0, 105, 106, 5, 70, 0, 0, 106, 107, 5, 82, 0, 0, 107, 108,
-		5, 79, 0, 0, 108, 109, 5, 77, 0, 0, 109, 20, 1, 0, 0, 0, 110, 111, 5, 70,
-		0, 0, 111, 112, 5, 73, 0, 0, 112, 113, 5, 76, 0, 0, 113, 114, 5, 84, 0,
-		0, 114, 115, 5, 69, 0, 0, 115, 116, 5, 82, 0, 0, 116, 22, 1, 0, 0, 0, 117,
-		118, 5, 42, 0, 0, 118, 24, 1, 0, 0, 0, 119, 120, 5, 83, 0, 0, 120, 121,
-		5, 65, 0, 0, 121, 122, 5, 77, 0, 0, 122, 123, 5, 69, 0, 0, 123, 26, 1,
-		0, 0, 0, 124, 125, 5, 68, 0, 0, 125, 126, 5, 73, 0, 0, 126, 127, 5, 83,
-		0, 0, 127, 128, 5, 84, 0, 0, 128, 129, 5, 73, 0, 0, 129, 130, 5, 78, 0,
-		0, 130, 131, 5, 67, 0, 0, 131, 132, 5, 84, 0, 0, 132, 28, 1, 0, 0, 0, 133,
-		134, 5, 40, 0, 0, 134, 30, 1, 0, 0, 0, 135, 136, 5, 41, 0, 0, 136, 32,
-		1, 0, 0, 0, 137, 138, 5, 64, 0, 0, 138, 34, 1, 0, 0, 0, 139, 144, 3, 39,
-		19, 0, 140, 143, 3, 37, 18, 0, 141, 143, 3, 39, 19, 0, 142, 140, 1, 0,
-		0, 0, 142, 141, 1, 0, 0, 0, 143, 146, 1, 0, 0, 0, 144, 142, 1, 0, 0, 0,
-		144, 145, 1, 0, 0, 0, 145, 36, 1, 0, 0, 0, 146, 144, 1, 0, 0, 0, 147, 148,
-		7, 0, 0, 0, 148, 38, 1, 0, 0, 0, 149, 150, 7, 1, 0, 0, 150, 40, 1, 0, 0,
-		0, 151, 155, 7, 2, 0, 0, 152, 154, 3, 37, 18, 0, 153, 152, 1, 0, 0, 0,
-		154, 157, 1, 0, 0, 0, 155, 153, 1, 0, 0, 0, 155, 156, 1, 0, 0, 0, 156,
-		42, 1, 0, 0, 0, 157, 155, 1, 0, 0, 0, 158, 159, 5, 48, 0, 0, 159, 44, 1,
-		0, 0, 0, 160, 165, 5, 34, 0, 0, 161, 164, 3, 47, 23, 0, 162, 164, 3, 55,
-		27, 0, 163, 161, 1, 0, 0, 0, 163, 162, 1, 0, 0, 0, 164, 167, 1, 0, 0, 0,
-		165, 163, 1, 0, 0, 0, 165, 166, 1, 0, 0, 0, 166, 168, 1, 0, 0, 0, 167,
-		165, 1, 0, 0, 0, 168, 179, 5, 34, 0, 0, 169, 174, 5, 39, 0, 0, 170, 173,
-		3, 47, 23, 0, 171, 173, 3, 53, 26, 0, 172, 170, 1, 0, 0, 0, 172, 171, 1,
-		0, 0, 0, 173, 176, 1, 0, 0, 0, 174, 172, 1, 0, 0, 0, 174, 175, 1, 0, 0,
-		0, 175, 177, 1, 0, 0, 0, 176, 174, 1, 0, 0, 0, 177, 179, 5, 39, 0, 0, 178,
-		160, 1, 0, 0, 0, 178, 169, 1, 0, 0, 0, 179, 46, 1, 0, 0, 0, 180, 183, 5,
-		92, 0, 0, 181, 184, 7, 3, 0, 0, 182, 184, 3, 49, 24, 0, 183, 181, 1, 0,
-		0, 0, 183, 182, 1, 0, 0, 0, 184, 48, 1, 0, 0, 0, 185, 186, 5, 117, 0, 0,
-		186, 187, 3, 51, 25, 0, 187, 188, 3, 51, 25, 0, 188, 189, 3, 51, 25, 0,
-		189, 190, 3, 51, 25, 0, 190, 50, 1, 0, 0, 0, 191, 192, 7, 4, 0, 0, 192,
-		52, 1, 0, 0, 0, 193, 194, 8, 5, 0, 0, 194, 54, 1, 0, 0, 0, 195, 196, 8,
-		6, 0, 0, 196, 56, 1, 0, 0, 0, 197, 199, 7, 7, 0, 0, 198, 197, 1, 0, 0,
-		0, 199, 200, 1, 0, 0, 0, 200, 198, 1, 0, 0, 0, 200, 201, 1, 0, 0, 0, 201,
-		202, 1, 0, 0, 0, 202, 203, 6, 28, 0, 0, 203, 58, 1, 0, 0, 0, 12, 0, 82,
-		142, 144, 155, 163, 165, 172, 174, 178, 183, 200, 1, 6, 0, 0,
+		2, 26, 7, 26, 2, 27, 7, 27, 2, 28, 7, 28, 2, 29, 7, 29, 1, 0, 1, 0, 1,
+		0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 3, 1,
+		3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 3, 3, 85, 8, 3, 1, 4,
+		1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 1, 5, 1, 6, 1, 6,
+		1, 6, 1, 7, 1, 7, 1, 7, 1, 8, 1, 8, 1, 8, 1, 8, 1, 9, 1, 9, 1, 9, 1, 9,
+		1, 9, 1, 9, 1, 9, 1, 10, 1, 10, 1, 10, 1, 10, 1, 10, 1, 11, 1, 11, 1, 11,
+		1, 11, 1, 11, 1, 11, 1, 11, 1, 12, 1, 12, 1, 13, 1, 13, 1, 13, 1, 13, 1,
+		13, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 14, 1, 15,
+		1, 15, 1, 16, 1, 16, 1, 17, 1, 17, 1, 18, 1, 18, 1, 18, 5, 18, 152, 8,
+		18, 10, 18, 12, 18, 155, 9, 18, 1, 19, 1, 19, 1, 20, 1, 20, 1, 21, 1, 21,
+		5, 21, 163, 8, 21, 10, 21, 12, 21, 166, 9, 21, 1, 22, 1, 22, 1, 23, 1,
+		23, 1, 23, 5, 23, 173, 8, 23, 10, 23, 12, 23, 176, 9, 23, 1, 23, 1, 23,
+		1, 23, 1, 23, 5, 23, 182, 8, 23, 10, 23, 12, 23, 185, 9, 23, 1, 23, 3,
+		23, 188, 8, 23, 1, 24, 1, 24, 1, 24, 3, 24, 193, 8, 24, 1, 25, 1, 25, 1,
+		25, 1, 25, 1, 25, 1, 25, 1, 26, 1, 26, 1, 27, 1, 27, 1, 28, 1, 28, 1, 29,
+		4, 29, 208, 8, 29, 11, 29, 12, 29, 209, 1, 29, 1, 29, 0, 0, 30, 1, 1, 3,
+		2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 15, 8, 17, 9, 19, 10, 21, 11, 23, 12,
+		25, 13, 27, 14, 29, 15, 31, 16, 33, 17, 35, 18, 37, 19, 39, 0, 41, 0, 43,
+		20, 45, 21, 47, 22, 49, 0, 51, 0, 53, 0, 55, 0, 57, 0, 59, 23, 1, 0, 8,
+		1, 0, 48, 57, 3, 0, 65, 90, 95, 95, 97, 122, 1, 0, 49, 57, 9, 0, 34, 34,
+		39, 39, 47, 47, 92, 92, 98, 98, 102, 102, 110, 110, 114, 114, 116, 116,
+		3, 0, 48, 57, 65, 70, 97, 102, 3, 0, 0, 31, 39, 39, 92, 92, 3, 0, 0, 31,
+		34, 34, 92, 92, 3, 0, 9, 10, 13, 13, 32, 32, 220, 0, 1, 1, 0, 0, 0, 0,
+		3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0,
+		11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 0, 15, 1, 0, 0, 0, 0, 17, 1, 0, 0, 0,
+		0, 19, 1, 0, 0, 0, 0, 21, 1, 0, 0, 0, 0, 23, 1, 0, 0, 0, 0, 25, 1, 0, 0,
+		0, 0, 27, 1, 0, 0, 0, 0, 29, 1, 0, 0, 0, 0, 31, 1, 0, 0, 0, 0, 33, 1, 0,
+		0, 0, 0, 35, 1, 0, 0, 0, 0, 37, 1, 0, 0, 0, 0, 43, 1, 0, 0, 0, 0, 45, 1,
+		0, 0, 0, 0, 47, 1, 0, 0, 0, 0, 59, 1, 0, 0, 0, 1, 61, 1, 0, 0, 0, 3, 65,
+		1, 0, 0, 0, 5, 69, 1, 0, 0, 0, 7, 84, 1, 0, 0, 0, 9, 86, 1, 0, 0, 0, 11,
+		93, 1, 0, 0, 0, 13, 97, 1, 0, 0, 0, 15, 100, 1, 0, 0, 0, 17, 103, 1, 0,
+		0, 0, 19, 107, 1, 0, 0, 0, 21, 114, 1, 0, 0, 0, 23, 119, 1, 0, 0, 0, 25,
+		126, 1, 0, 0, 0, 27, 128, 1, 0, 0, 0, 29, 133, 1, 0, 0, 0, 31, 142, 1,
+		0, 0, 0, 33, 144, 1, 0, 0, 0, 35, 146, 1, 0, 0, 0, 37, 148, 1, 0, 0, 0,
+		39, 156, 1, 0, 0, 0, 41, 158, 1, 0, 0, 0, 43, 160, 1, 0, 0, 0, 45, 167,
+		1, 0, 0, 0, 47, 187, 1, 0, 0, 0, 49, 189, 1, 0, 0, 0, 51, 194, 1, 0, 0,
+		0, 53, 200, 1, 0, 0, 0, 55, 202, 1, 0, 0, 0, 57, 204, 1, 0, 0, 0, 59, 207,
+		1, 0, 0, 0, 61, 62, 5, 78, 0, 0, 62, 63, 5, 79, 0, 0, 63, 64, 5, 84, 0,
+		0, 64, 2, 1, 0, 0, 0, 65, 66, 5, 65, 0, 0, 66, 67, 5, 78, 0, 0, 67, 68,
+		5, 68, 0, 0, 68, 4, 1, 0, 0, 0, 69, 70, 5, 79, 0, 0, 70, 71, 5, 82, 0,
+		0, 71, 6, 1, 0, 0, 0, 72, 73, 5, 69, 0, 0, 73, 85, 5, 81, 0, 0, 74, 75,
+		5, 78, 0, 0, 75, 85, 5, 69, 0, 0, 76, 77, 5, 71, 0, 0, 77, 85, 5, 69, 0,
+		0, 78, 79, 5, 71, 0, 0, 79, 85, 5, 84, 0, 0, 80, 81, 5, 76, 0, 0, 81, 85,
+		5, 84, 0, 0, 82, 83, 5, 76, 0, 0, 83, 85, 5, 69, 0, 0, 84, 72, 1, 0, 0,
+		0, 84, 74, 1, 0, 0, 0, 84, 76, 1, 0, 0, 0, 84, 78, 1, 0, 0, 0, 84, 80,
+		1, 0, 0, 0, 84, 82, 1, 0, 0, 0, 85, 8, 1, 0, 0, 0, 86, 87, 5, 85, 0, 0,
+		87, 88, 5, 78, 0, 0, 88, 89, 5, 73, 0, 0, 89, 90, 5, 81, 0, 0, 90, 91,
+		5, 85, 0, 0, 91, 92, 5, 69, 0, 0, 92, 10, 1, 0, 0, 0, 93, 94, 5, 82, 0,
+		0, 94, 95, 5, 69, 0, 0, 95, 96, 5, 80, 0, 0, 96, 12, 1, 0, 0, 0, 97, 98,
+		5, 73, 0, 0, 98, 99, 5, 78, 0, 0, 99, 14, 1, 0, 0, 0, 100, 101, 5, 65,
+		0, 0, 101, 102, 5, 83, 0, 0, 102, 16, 1, 0, 0, 0, 103, 104, 5, 67, 0, 0,
+		104, 105, 5, 66, 0, 0, 105, 106, 5, 70, 0, 0, 106, 18, 1, 0, 0, 0, 107,
+		108, 5, 83, 0, 0, 108, 109, 5, 69, 0, 0, 109, 110, 5, 76, 0, 0, 110, 111,
+		5, 69, 0, 0, 111, 112, 5, 67, 0, 0, 112, 113, 5, 84, 0, 0, 113, 20, 1,
+		0, 0, 0, 114, 115, 5, 70, 0, 0, 115, 116, 5, 82, 0, 0, 116, 117, 5, 79,
+		0, 0, 117, 118, 5, 77, 0, 0, 118, 22, 1, 0, 0, 0, 119, 120, 5, 70, 0, 0,
+		120, 121, 5, 73, 0, 0, 121, 122, 5, 76, 0, 0, 122, 123, 5, 84, 0, 0, 123,
+		124, 5, 69, 0, 0, 124, 125, 5, 82, 0, 0, 125, 24, 1, 0, 0, 0, 126, 127,
+		5, 42, 0, 0, 127, 26, 1, 0, 0, 0, 128, 129, 5, 83, 0, 0, 129, 130, 5, 65,
+		0, 0, 130, 131, 5, 77, 0, 0, 131, 132, 5, 69, 0, 0, 132, 28, 1, 0, 0, 0,
+		133, 134, 5, 68, 0, 0, 134, 135, 5, 73, 0, 0, 135, 136, 5, 83, 0, 0, 136,
+		137, 5, 84, 0, 0, 137, 138, 5, 73, 0, 0, 138, 139, 5, 78, 0, 0, 139, 140,
+		5, 67, 0, 0, 140, 141, 5, 84, 0, 0, 141, 30, 1, 0, 0, 0, 142, 143, 5, 40,
+		0, 0, 143, 32, 1, 0, 0, 0, 144, 145, 5, 41, 0, 0, 145, 34, 1, 0, 0, 0,
+		146, 147, 5, 64, 0, 0, 147, 36, 1, 0, 0, 0, 148, 153, 3, 41, 20, 0, 149,
+		152, 3, 39, 19, 0, 150, 152, 3, 41, 20, 0, 151, 149, 1, 0, 0, 0, 151, 150,
+		1, 0, 0, 0, 152, 155, 1, 0, 0, 0, 153, 151, 1, 0, 0, 0, 153, 154, 1, 0,
+		0, 0, 154, 38, 1, 0, 0, 0, 155, 153, 1, 0, 0, 0, 156, 157, 7, 0, 0, 0,
+		157, 40, 1, 0, 0, 0, 158, 159, 7, 1, 0, 0, 159, 42, 1, 0, 0, 0, 160, 164,
+		7, 2, 0, 0, 161, 163, 3, 39, 19, 0, 162, 161, 1, 0, 0, 0, 163, 166, 1,
+		0, 0, 0, 164, 162, 1, 0, 0, 0, 164, 165, 1, 0, 0, 0, 165, 44, 1, 0, 0,
+		0, 166, 164, 1, 0, 0, 0, 167, 168, 5, 48, 0, 0, 168, 46, 1, 0, 0, 0, 169,
+		174, 5, 34, 0, 0, 170, 173, 3, 49, 24, 0, 171, 173, 3, 57, 28, 0, 172,
+		170, 1, 0, 0, 0, 172, 171, 1, 0, 0, 0, 173, 176, 1, 0, 0, 0, 174, 172,
+		1, 0, 0, 0, 174, 175, 1, 0, 0, 0, 175, 177, 1, 0, 0, 0, 176, 174, 1, 0,
+		0, 0, 177, 188, 5, 34, 0, 0, 178, 183, 5, 39, 0, 0, 179, 182, 3, 49, 24,
+		0, 180, 182, 3, 55, 27, 0, 181, 179, 1, 0, 0, 0, 181, 180, 1, 0, 0, 0,
+		182, 185, 1, 0, 0, 0, 183, 181, 1, 0, 0, 0, 183, 184, 1, 0, 0, 0, 184,
+		186, 1, 0, 0, 0, 185, 183, 1, 0, 0, 0, 186, 188, 5, 39, 0, 0, 187, 169,
+		1, 0, 0, 0, 187, 178, 1, 0, 0, 0, 188, 48, 1, 0, 0, 0, 189, 192, 5, 92,
+		0, 0, 190, 193, 7, 3, 0, 0, 191, 193, 3, 51, 25, 0, 192, 190, 1, 0, 0,
+		0, 192, 191, 1, 0, 0, 0, 193, 50, 1, 0, 0, 0, 194, 195, 5, 117, 0, 0, 195,
+		196, 3, 53, 26, 0, 196, 197, 3, 53, 26, 0, 197, 198, 3, 53, 26, 0, 198,
+		199, 3, 53, 26, 0, 199, 52, 1, 0, 0, 0, 200, 201, 7, 4, 0, 0, 201, 54,
+		1, 0, 0, 0, 202, 203, 8, 5, 0, 0, 203, 56, 1, 0, 0, 0, 204, 205, 8, 6,
+		0, 0, 205, 58, 1, 0, 0, 0, 206, 208, 7, 7, 0, 0, 207, 206, 1, 0, 0, 0,
+		208, 209, 1, 0, 0, 0, 209, 207, 1, 0, 0, 0, 209, 210, 1, 0, 0, 0, 210,
+		211, 1, 0, 0, 0, 211, 212, 6, 29, 0, 0, 212, 60, 1, 0, 0, 0, 12, 0, 84,
+		151, 153, 164, 172, 174, 181, 183, 187, 192, 209, 1, 6, 0, 0,
 	}
 	deserializer := antlr.NewATNDeserializer(nil)
 	staticData.atn = deserializer.Deserialize(staticData.serializedATN)
@@ -194,22 +200,23 @@ const (
 	QueryLexerAND_OP          = 2
 	QueryLexerOR_OP           = 3
 	QueryLexerSIMPLE_OP       = 4
-	QueryLexerREP             = 5
-	QueryLexerIN              = 6
-	QueryLexerAS              = 7
-	QueryLexerCBF             = 8
-	QueryLexerSELECT          = 9
-	QueryLexerFROM            = 10
-	QueryLexerFILTER          = 11
-	QueryLexerWILDCARD        = 12
-	QueryLexerCLAUSE_SAME     = 13
-	QueryLexerCLAUSE_DISTINCT = 14
-	QueryLexerL_PAREN         = 15
-	QueryLexerR_PAREN         = 16
-	QueryLexerAT              = 17
-	QueryLexerIDENT           = 18
-	QueryLexerNUMBER1         = 19
-	QueryLexerZERO            = 20
-	QueryLexerSTRING          = 21
-	QueryLexerWS              = 22
+	QueryLexerUNIQUE          = 5
+	QueryLexerREP             = 6
+	QueryLexerIN              = 7
+	QueryLexerAS              = 8
+	QueryLexerCBF             = 9
+	QueryLexerSELECT          = 10
+	QueryLexerFROM            = 11
+	QueryLexerFILTER          = 12
+	QueryLexerWILDCARD        = 13
+	QueryLexerCLAUSE_SAME     = 14
+	QueryLexerCLAUSE_DISTINCT = 15
+	QueryLexerL_PAREN         = 16
+	QueryLexerR_PAREN         = 17
+	QueryLexerAT              = 18
+	QueryLexerIDENT           = 19
+	QueryLexerNUMBER1         = 20
+	QueryLexerZERO            = 21
+	QueryLexerSTRING          = 22
+	QueryLexerWS              = 23
 )
diff --git a/netmap/parser/query_parser.go b/netmap/parser/query_parser.go
index 3dda93e..6357727 100644
--- a/netmap/parser/query_parser.go
+++ b/netmap/parser/query_parser.go
@@ -1,3 +1,5 @@
+// Code generated from Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
+
 package parser // Query
 
 import (
@@ -31,14 +33,15 @@ var QueryParserStaticData struct {
 func queryParserInit() {
 	staticData := &QueryParserStaticData
 	staticData.LiteralNames = []string{
-		"", "'NOT'", "'AND'", "'OR'", "", "'REP'", "'IN'", "'AS'", "'CBF'",
-		"'SELECT'", "'FROM'", "'FILTER'", "'*'", "'SAME'", "'DISTINCT'", "'('",
-		"')'", "'@'", "", "", "'0'",
+		"", "'NOT'", "'AND'", "'OR'", "", "'UNIQUE'", "'REP'", "'IN'", "'AS'",
+		"'CBF'", "'SELECT'", "'FROM'", "'FILTER'", "'*'", "'SAME'", "'DISTINCT'",
+		"'('", "')'", "'@'", "", "", "'0'",
 	}
 	staticData.SymbolicNames = []string{
-		"", "NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "REP", "IN", "AS", "CBF",
-		"SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME", "CLAUSE_DISTINCT",
-		"L_PAREN", "R_PAREN", "AT", "IDENT", "NUMBER1", "ZERO", "STRING", "WS",
+		"", "NOT_OP", "AND_OP", "OR_OP", "SIMPLE_OP", "UNIQUE", "REP", "IN",
+		"AS", "CBF", "SELECT", "FROM", "FILTER", "WILDCARD", "CLAUSE_SAME",
+		"CLAUSE_DISTINCT", "L_PAREN", "R_PAREN", "AT", "IDENT", "NUMBER1", "ZERO",
+		"STRING", "WS",
 	}
 	staticData.RuleNames = []string{
 		"policy", "repStmt", "cbfStmt", "selectStmt", "clause", "filterExpr",
@@ -47,62 +50,64 @@ func queryParserInit() {
 	}
 	staticData.PredictionContextCache = antlr.NewPredictionContextCache()
 	staticData.serializedATN = []int32{
-		4, 1, 22, 135, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2, 4, 7,
+		4, 1, 23, 138, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2, 4, 7,
 		4, 2, 5, 7, 5, 2, 6, 7, 6, 2, 7, 7, 7, 2, 8, 7, 8, 2, 9, 7, 9, 2, 10, 7,
-		10, 2, 11, 7, 11, 2, 12, 7, 12, 2, 13, 7, 13, 1, 0, 4, 0, 30, 8, 0, 11,
-		0, 12, 0, 31, 1, 0, 3, 0, 35, 8, 0, 1, 0, 5, 0, 38, 8, 0, 10, 0, 12, 0,
-		41, 9, 0, 1, 0, 5, 0, 44, 8, 0, 10, 0, 12, 0, 47, 9, 0, 1, 0, 1, 0, 1,
-		1, 1, 1, 1, 1, 1, 1, 3, 1, 55, 8, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 3,
-		1, 3, 3, 3, 64, 8, 3, 1, 3, 3, 3, 67, 8, 3, 1, 3, 1, 3, 1, 3, 1, 3, 3,
-		3, 73, 8, 3, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5,
-		1, 5, 1, 5, 1, 5, 3, 5, 88, 8, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 5,
-		5, 96, 8, 5, 10, 5, 12, 5, 99, 9, 5, 1, 6, 1, 6, 1, 6, 1, 6, 1, 6, 1, 7,
-		1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 3, 7, 112, 8, 7, 1, 8, 1, 8, 3, 8, 116, 8,
-		8, 1, 9, 1, 9, 1, 9, 3, 9, 121, 8, 9, 1, 10, 1, 10, 1, 11, 1, 11, 1, 12,
-		1, 12, 3, 12, 129, 8, 12, 1, 13, 1, 13, 3, 13, 133, 8, 13, 1, 13, 0, 1,
-		10, 14, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 0, 3, 1, 0,
-		13, 14, 1, 0, 19, 20, 2, 0, 5, 7, 9, 11, 138, 0, 29, 1, 0, 0, 0, 2, 50,
-		1, 0, 0, 0, 4, 56, 1, 0, 0, 0, 6, 59, 1, 0, 0, 0, 8, 74, 1, 0, 0, 0, 10,
-		87, 1, 0, 0, 0, 12, 100, 1, 0, 0, 0, 14, 111, 1, 0, 0, 0, 16, 115, 1, 0,
-		0, 0, 18, 120, 1, 0, 0, 0, 20, 122, 1, 0, 0, 0, 22, 124, 1, 0, 0, 0, 24,
-		128, 1, 0, 0, 0, 26, 132, 1, 0, 0, 0, 28, 30, 3, 2, 1, 0, 29, 28, 1, 0,
-		0, 0, 30, 31, 1, 0, 0, 0, 31, 29, 1, 0, 0, 0, 31, 32, 1, 0, 0, 0, 32, 34,
-		1, 0, 0, 0, 33, 35, 3, 4, 2, 0, 34, 33, 1, 0, 0, 0, 34, 35, 1, 0, 0, 0,
-		35, 39, 1, 0, 0, 0, 36, 38, 3, 6, 3, 0, 37, 36, 1, 0, 0, 0, 38, 41, 1,
-		0, 0, 0, 39, 37, 1, 0, 0, 0, 39, 40, 1, 0, 0, 0, 40, 45, 1, 0, 0, 0, 41,
-		39, 1, 0, 0, 0, 42, 44, 3, 12, 6, 0, 43, 42, 1, 0, 0, 0, 44, 47, 1, 0,
-		0, 0, 45, 43, 1, 0, 0, 0, 45, 46, 1, 0, 0, 0, 46, 48, 1, 0, 0, 0, 47, 45,
-		1, 0, 0, 0, 48, 49, 5, 0, 0, 1, 49, 1, 1, 0, 0, 0, 50, 51, 5, 5, 0, 0,
-		51, 54, 5, 19, 0, 0, 52, 53, 5, 6, 0, 0, 53, 55, 3, 24, 12, 0, 54, 52,
-		1, 0, 0, 0, 54, 55, 1, 0, 0, 0, 55, 3, 1, 0, 0, 0, 56, 57, 5, 8, 0, 0,
-		57, 58, 5, 19, 0, 0, 58, 5, 1, 0, 0, 0, 59, 60, 5, 9, 0, 0, 60, 66, 5,
-		19, 0, 0, 61, 63, 5, 6, 0, 0, 62, 64, 3, 8, 4, 0, 63, 62, 1, 0, 0, 0, 63,
-		64, 1, 0, 0, 0, 64, 65, 1, 0, 0, 0, 65, 67, 3, 24, 12, 0, 66, 61, 1, 0,
-		0, 0, 66, 67, 1, 0, 0, 0, 67, 68, 1, 0, 0, 0, 68, 69, 5, 10, 0, 0, 69,
-		72, 3, 26, 13, 0, 70, 71, 5, 7, 0, 0, 71, 73, 3, 24, 12, 0, 72, 70, 1,
-		0, 0, 0, 72, 73, 1, 0, 0, 0, 73, 7, 1, 0, 0, 0, 74, 75, 7, 0, 0, 0, 75,
-		9, 1, 0, 0, 0, 76, 77, 6, 5, -1, 0, 77, 78, 5, 1, 0, 0, 78, 79, 5, 15,
-		0, 0, 79, 80, 3, 10, 5, 0, 80, 81, 5, 16, 0, 0, 81, 88, 1, 0, 0, 0, 82,
-		83, 5, 15, 0, 0, 83, 84, 3, 10, 5, 0, 84, 85, 5, 16, 0, 0, 85, 88, 1, 0,
-		0, 0, 86, 88, 3, 14, 7, 0, 87, 76, 1, 0, 0, 0, 87, 82, 1, 0, 0, 0, 87,
-		86, 1, 0, 0, 0, 88, 97, 1, 0, 0, 0, 89, 90, 10, 4, 0, 0, 90, 91, 5, 2,
-		0, 0, 91, 96, 3, 10, 5, 5, 92, 93, 10, 3, 0, 0, 93, 94, 5, 3, 0, 0, 94,
-		96, 3, 10, 5, 4, 95, 89, 1, 0, 0, 0, 95, 92, 1, 0, 0, 0, 96, 99, 1, 0,
-		0, 0, 97, 95, 1, 0, 0, 0, 97, 98, 1, 0, 0, 0, 98, 11, 1, 0, 0, 0, 99, 97,
-		1, 0, 0, 0, 100, 101, 5, 11, 0, 0, 101, 102, 3, 10, 5, 0, 102, 103, 5,
-		7, 0, 0, 103, 104, 3, 24, 12, 0, 104, 13, 1, 0, 0, 0, 105, 106, 5, 17,
-		0, 0, 106, 112, 3, 24, 12, 0, 107, 108, 3, 16, 8, 0, 108, 109, 5, 4, 0,
-		0, 109, 110, 3, 18, 9, 0, 110, 112, 1, 0, 0, 0, 111, 105, 1, 0, 0, 0, 111,
-		107, 1, 0, 0, 0, 112, 15, 1, 0, 0, 0, 113, 116, 3, 24, 12, 0, 114, 116,
-		5, 21, 0, 0, 115, 113, 1, 0, 0, 0, 115, 114, 1, 0, 0, 0, 116, 17, 1, 0,
-		0, 0, 117, 121, 3, 24, 12, 0, 118, 121, 3, 20, 10, 0, 119, 121, 5, 21,
-		0, 0, 120, 117, 1, 0, 0, 0, 120, 118, 1, 0, 0, 0, 120, 119, 1, 0, 0, 0,
-		121, 19, 1, 0, 0, 0, 122, 123, 7, 1, 0, 0, 123, 21, 1, 0, 0, 0, 124, 125,
-		7, 2, 0, 0, 125, 23, 1, 0, 0, 0, 126, 129, 3, 22, 11, 0, 127, 129, 5, 18,
-		0, 0, 128, 126, 1, 0, 0, 0, 128, 127, 1, 0, 0, 0, 129, 25, 1, 0, 0, 0,
-		130, 133, 3, 24, 12, 0, 131, 133, 5, 12, 0, 0, 132, 130, 1, 0, 0, 0, 132,
-		131, 1, 0, 0, 0, 133, 27, 1, 0, 0, 0, 16, 31, 34, 39, 45, 54, 63, 66, 72,
-		87, 95, 97, 111, 115, 120, 128, 132,
+		10, 2, 11, 7, 11, 2, 12, 7, 12, 2, 13, 7, 13, 1, 0, 3, 0, 30, 8, 0, 1,
+		0, 4, 0, 33, 8, 0, 11, 0, 12, 0, 34, 1, 0, 3, 0, 38, 8, 0, 1, 0, 5, 0,
+		41, 8, 0, 10, 0, 12, 0, 44, 9, 0, 1, 0, 5, 0, 47, 8, 0, 10, 0, 12, 0, 50,
+		9, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 58, 8, 1, 1, 2, 1, 2, 1,
+		2, 1, 3, 1, 3, 1, 3, 1, 3, 3, 3, 67, 8, 3, 1, 3, 3, 3, 70, 8, 3, 1, 3,
+		1, 3, 1, 3, 1, 3, 3, 3, 76, 8, 3, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 1, 5, 1,
+		5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 3, 5, 91, 8, 5, 1, 5, 1, 5, 1, 5,
+		1, 5, 1, 5, 1, 5, 5, 5, 99, 8, 5, 10, 5, 12, 5, 102, 9, 5, 1, 6, 1, 6,
+		1, 6, 1, 6, 1, 6, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 3, 7, 115, 8, 7,
+		1, 8, 1, 8, 3, 8, 119, 8, 8, 1, 9, 1, 9, 1, 9, 3, 9, 124, 8, 9, 1, 10,
+		1, 10, 1, 11, 1, 11, 1, 12, 1, 12, 3, 12, 132, 8, 12, 1, 13, 1, 13, 3,
+		13, 136, 8, 13, 1, 13, 0, 1, 10, 14, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18,
+		20, 22, 24, 26, 0, 3, 1, 0, 14, 15, 1, 0, 20, 21, 2, 0, 6, 8, 10, 12, 142,
+		0, 29, 1, 0, 0, 0, 2, 53, 1, 0, 0, 0, 4, 59, 1, 0, 0, 0, 6, 62, 1, 0, 0,
+		0, 8, 77, 1, 0, 0, 0, 10, 90, 1, 0, 0, 0, 12, 103, 1, 0, 0, 0, 14, 114,
+		1, 0, 0, 0, 16, 118, 1, 0, 0, 0, 18, 123, 1, 0, 0, 0, 20, 125, 1, 0, 0,
+		0, 22, 127, 1, 0, 0, 0, 24, 131, 1, 0, 0, 0, 26, 135, 1, 0, 0, 0, 28, 30,
+		5, 5, 0, 0, 29, 28, 1, 0, 0, 0, 29, 30, 1, 0, 0, 0, 30, 32, 1, 0, 0, 0,
+		31, 33, 3, 2, 1, 0, 32, 31, 1, 0, 0, 0, 33, 34, 1, 0, 0, 0, 34, 32, 1,
+		0, 0, 0, 34, 35, 1, 0, 0, 0, 35, 37, 1, 0, 0, 0, 36, 38, 3, 4, 2, 0, 37,
+		36, 1, 0, 0, 0, 37, 38, 1, 0, 0, 0, 38, 42, 1, 0, 0, 0, 39, 41, 3, 6, 3,
+		0, 40, 39, 1, 0, 0, 0, 41, 44, 1, 0, 0, 0, 42, 40, 1, 0, 0, 0, 42, 43,
+		1, 0, 0, 0, 43, 48, 1, 0, 0, 0, 44, 42, 1, 0, 0, 0, 45, 47, 3, 12, 6, 0,
+		46, 45, 1, 0, 0, 0, 47, 50, 1, 0, 0, 0, 48, 46, 1, 0, 0, 0, 48, 49, 1,
+		0, 0, 0, 49, 51, 1, 0, 0, 0, 50, 48, 1, 0, 0, 0, 51, 52, 5, 0, 0, 1, 52,
+		1, 1, 0, 0, 0, 53, 54, 5, 6, 0, 0, 54, 57, 5, 20, 0, 0, 55, 56, 5, 7, 0,
+		0, 56, 58, 3, 24, 12, 0, 57, 55, 1, 0, 0, 0, 57, 58, 1, 0, 0, 0, 58, 3,
+		1, 0, 0, 0, 59, 60, 5, 9, 0, 0, 60, 61, 5, 20, 0, 0, 61, 5, 1, 0, 0, 0,
+		62, 63, 5, 10, 0, 0, 63, 69, 5, 20, 0, 0, 64, 66, 5, 7, 0, 0, 65, 67, 3,
+		8, 4, 0, 66, 65, 1, 0, 0, 0, 66, 67, 1, 0, 0, 0, 67, 68, 1, 0, 0, 0, 68,
+		70, 3, 24, 12, 0, 69, 64, 1, 0, 0, 0, 69, 70, 1, 0, 0, 0, 70, 71, 1, 0,
+		0, 0, 71, 72, 5, 11, 0, 0, 72, 75, 3, 26, 13, 0, 73, 74, 5, 8, 0, 0, 74,
+		76, 3, 24, 12, 0, 75, 73, 1, 0, 0, 0, 75, 76, 1, 0, 0, 0, 76, 7, 1, 0,
+		0, 0, 77, 78, 7, 0, 0, 0, 78, 9, 1, 0, 0, 0, 79, 80, 6, 5, -1, 0, 80, 81,
+		5, 1, 0, 0, 81, 82, 5, 16, 0, 0, 82, 83, 3, 10, 5, 0, 83, 84, 5, 17, 0,
+		0, 84, 91, 1, 0, 0, 0, 85, 86, 5, 16, 0, 0, 86, 87, 3, 10, 5, 0, 87, 88,
+		5, 17, 0, 0, 88, 91, 1, 0, 0, 0, 89, 91, 3, 14, 7, 0, 90, 79, 1, 0, 0,
+		0, 90, 85, 1, 0, 0, 0, 90, 89, 1, 0, 0, 0, 91, 100, 1, 0, 0, 0, 92, 93,
+		10, 4, 0, 0, 93, 94, 5, 2, 0, 0, 94, 99, 3, 10, 5, 5, 95, 96, 10, 3, 0,
+		0, 96, 97, 5, 3, 0, 0, 97, 99, 3, 10, 5, 4, 98, 92, 1, 0, 0, 0, 98, 95,
+		1, 0, 0, 0, 99, 102, 1, 0, 0, 0, 100, 98, 1, 0, 0, 0, 100, 101, 1, 0, 0,
+		0, 101, 11, 1, 0, 0, 0, 102, 100, 1, 0, 0, 0, 103, 104, 5, 12, 0, 0, 104,
+		105, 3, 10, 5, 0, 105, 106, 5, 8, 0, 0, 106, 107, 3, 24, 12, 0, 107, 13,
+		1, 0, 0, 0, 108, 109, 5, 18, 0, 0, 109, 115, 3, 24, 12, 0, 110, 111, 3,
+		16, 8, 0, 111, 112, 5, 4, 0, 0, 112, 113, 3, 18, 9, 0, 113, 115, 1, 0,
+		0, 0, 114, 108, 1, 0, 0, 0, 114, 110, 1, 0, 0, 0, 115, 15, 1, 0, 0, 0,
+		116, 119, 3, 24, 12, 0, 117, 119, 5, 22, 0, 0, 118, 116, 1, 0, 0, 0, 118,
+		117, 1, 0, 0, 0, 119, 17, 1, 0, 0, 0, 120, 124, 3, 24, 12, 0, 121, 124,
+		3, 20, 10, 0, 122, 124, 5, 22, 0, 0, 123, 120, 1, 0, 0, 0, 123, 121, 1,
+		0, 0, 0, 123, 122, 1, 0, 0, 0, 124, 19, 1, 0, 0, 0, 125, 126, 7, 1, 0,
+		0, 126, 21, 1, 0, 0, 0, 127, 128, 7, 2, 0, 0, 128, 23, 1, 0, 0, 0, 129,
+		132, 3, 22, 11, 0, 130, 132, 5, 19, 0, 0, 131, 129, 1, 0, 0, 0, 131, 130,
+		1, 0, 0, 0, 132, 25, 1, 0, 0, 0, 133, 136, 3, 24, 12, 0, 134, 136, 5, 13,
+		0, 0, 135, 133, 1, 0, 0, 0, 135, 134, 1, 0, 0, 0, 136, 27, 1, 0, 0, 0,
+		17, 29, 34, 37, 42, 48, 57, 66, 69, 75, 90, 98, 100, 114, 118, 123, 131,
+		135,
 	}
 	deserializer := antlr.NewATNDeserializer(nil)
 	staticData.atn = deserializer.Deserialize(staticData.serializedATN)
@@ -145,24 +150,25 @@ const (
 	QueryAND_OP          = 2
 	QueryOR_OP           = 3
 	QuerySIMPLE_OP       = 4
-	QueryREP             = 5
-	QueryIN              = 6
-	QueryAS              = 7
-	QueryCBF             = 8
-	QuerySELECT          = 9
-	QueryFROM            = 10
-	QueryFILTER          = 11
-	QueryWILDCARD        = 12
-	QueryCLAUSE_SAME     = 13
-	QueryCLAUSE_DISTINCT = 14
-	QueryL_PAREN         = 15
-	QueryR_PAREN         = 16
-	QueryAT              = 17
-	QueryIDENT           = 18
-	QueryNUMBER1         = 19
-	QueryZERO            = 20
-	QuerySTRING          = 21
-	QueryWS              = 22
+	QueryUNIQUE          = 5
+	QueryREP             = 6
+	QueryIN              = 7
+	QueryAS              = 8
+	QueryCBF             = 9
+	QuerySELECT          = 10
+	QueryFROM            = 11
+	QueryFILTER          = 12
+	QueryWILDCARD        = 13
+	QueryCLAUSE_SAME     = 14
+	QueryCLAUSE_DISTINCT = 15
+	QueryL_PAREN         = 16
+	QueryR_PAREN         = 17
+	QueryAT              = 18
+	QueryIDENT           = 19
+	QueryNUMBER1         = 20
+	QueryZERO            = 21
+	QuerySTRING          = 22
+	QueryWS              = 23
 )
 
 // Query rules.
@@ -192,6 +198,7 @@ type IPolicyContext interface {
 
 	// Getter signatures
 	EOF() antlr.TerminalNode
+	UNIQUE() antlr.TerminalNode
 	AllRepStmt() []IRepStmtContext
 	RepStmt(i int) IRepStmtContext
 	CbfStmt() ICbfStmtContext
@@ -240,6 +247,10 @@ func (s *PolicyContext) EOF() antlr.TerminalNode {
 	return s.GetToken(QueryEOF, 0)
 }
 
+func (s *PolicyContext) UNIQUE() antlr.TerminalNode {
+	return s.GetToken(QueryUNIQUE, 0)
+}
+
 func (s *PolicyContext) AllRepStmt() []IRepStmtContext {
 	children := s.GetChildren()
 	len := 0
@@ -410,20 +421,38 @@ func (p *Query) Policy() (localctx IPolicyContext) {
 	}
 	_la = p.GetTokenStream().LA(1)
 
-	for ok := true; ok; ok = _la == QueryREP {
+	if _la == QueryUNIQUE {
 		{
 			p.SetState(28)
+			p.Match(QueryUNIQUE)
+			if p.HasError() {
+				// Recognition error - abort rule
+				goto errorExit
+			}
+		}
+
+	}
+	p.SetState(32)
+	p.GetErrorHandler().Sync(p)
+	if p.HasError() {
+		goto errorExit
+	}
+	_la = p.GetTokenStream().LA(1)
+
+	for ok := true; ok; ok = _la == QueryREP {
+		{
+			p.SetState(31)
 			p.RepStmt()
 		}
 
-		p.SetState(31)
+		p.SetState(34)
 		p.GetErrorHandler().Sync(p)
 		if p.HasError() {
 			goto errorExit
 		}
 		_la = p.GetTokenStream().LA(1)
 	}
-	p.SetState(34)
+	p.SetState(37)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -432,12 +461,12 @@ func (p *Query) Policy() (localctx IPolicyContext) {
 
 	if _la == QueryCBF {
 		{
-			p.SetState(33)
+			p.SetState(36)
 			p.CbfStmt()
 		}
 
 	}
-	p.SetState(39)
+	p.SetState(42)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -446,18 +475,18 @@ func (p *Query) Policy() (localctx IPolicyContext) {
 
 	for _la == QuerySELECT {
 		{
-			p.SetState(36)
+			p.SetState(39)
 			p.SelectStmt()
 		}
 
-		p.SetState(41)
+		p.SetState(44)
 		p.GetErrorHandler().Sync(p)
 		if p.HasError() {
 			goto errorExit
 		}
 		_la = p.GetTokenStream().LA(1)
 	}
-	p.SetState(45)
+	p.SetState(48)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -466,11 +495,11 @@ func (p *Query) Policy() (localctx IPolicyContext) {
 
 	for _la == QueryFILTER {
 		{
-			p.SetState(42)
+			p.SetState(45)
 			p.FilterStmt()
 		}
 
-		p.SetState(47)
+		p.SetState(50)
 		p.GetErrorHandler().Sync(p)
 		if p.HasError() {
 			goto errorExit
@@ -478,7 +507,7 @@ func (p *Query) Policy() (localctx IPolicyContext) {
 		_la = p.GetTokenStream().LA(1)
 	}
 	{
-		p.SetState(48)
+		p.SetState(51)
 		p.Match(QueryEOF)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -623,7 +652,7 @@ func (p *Query) RepStmt() (localctx IRepStmtContext) {
 
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(50)
+		p.SetState(53)
 		p.Match(QueryREP)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -631,7 +660,7 @@ func (p *Query) RepStmt() (localctx IRepStmtContext) {
 		}
 	}
 	{
-		p.SetState(51)
+		p.SetState(54)
 
 		var _m = p.Match(QueryNUMBER1)
 
@@ -641,7 +670,7 @@ func (p *Query) RepStmt() (localctx IRepStmtContext) {
 			goto errorExit
 		}
 	}
-	p.SetState(54)
+	p.SetState(57)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -650,7 +679,7 @@ func (p *Query) RepStmt() (localctx IRepStmtContext) {
 
 	if _la == QueryIN {
 		{
-			p.SetState(52)
+			p.SetState(55)
 			p.Match(QueryIN)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -658,7 +687,7 @@ func (p *Query) RepStmt() (localctx IRepStmtContext) {
 			}
 		}
 		{
-			p.SetState(53)
+			p.SetState(56)
 
 			var _x = p.Ident()
 
@@ -769,7 +798,7 @@ func (p *Query) CbfStmt() (localctx ICbfStmtContext) {
 	p.EnterRule(localctx, 4, QueryRULE_cbfStmt)
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(56)
+		p.SetState(59)
 		p.Match(QueryCBF)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -777,7 +806,7 @@ func (p *Query) CbfStmt() (localctx ICbfStmtContext) {
 		}
 	}
 	{
-		p.SetState(57)
+		p.SetState(60)
 
 		var _m = p.Match(QueryNUMBER1)
 
@@ -1017,7 +1046,7 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(59)
+		p.SetState(62)
 		p.Match(QuerySELECT)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -1025,7 +1054,7 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 		}
 	}
 	{
-		p.SetState(60)
+		p.SetState(63)
 
 		var _m = p.Match(QueryNUMBER1)
 
@@ -1035,7 +1064,7 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 			goto errorExit
 		}
 	}
-	p.SetState(66)
+	p.SetState(69)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -1044,14 +1073,14 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 
 	if _la == QueryIN {
 		{
-			p.SetState(61)
+			p.SetState(64)
 			p.Match(QueryIN)
 			if p.HasError() {
 				// Recognition error - abort rule
 				goto errorExit
 			}
 		}
-		p.SetState(63)
+		p.SetState(66)
 		p.GetErrorHandler().Sync(p)
 		if p.HasError() {
 			goto errorExit
@@ -1060,13 +1089,13 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 
 		if _la == QueryCLAUSE_SAME || _la == QueryCLAUSE_DISTINCT {
 			{
-				p.SetState(62)
+				p.SetState(65)
 				p.Clause()
 			}
 
 		}
 		{
-			p.SetState(65)
+			p.SetState(68)
 
 			var _x = p.Ident()
 
@@ -1075,7 +1104,7 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 
 	}
 	{
-		p.SetState(68)
+		p.SetState(71)
 		p.Match(QueryFROM)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -1083,13 +1112,13 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 		}
 	}
 	{
-		p.SetState(69)
+		p.SetState(72)
 
 		var _x = p.IdentWC()
 
 		localctx.(*SelectStmtContext).Filter = _x
 	}
-	p.SetState(72)
+	p.SetState(75)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -1098,7 +1127,7 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 
 	if _la == QueryAS {
 		{
-			p.SetState(70)
+			p.SetState(73)
 			p.Match(QueryAS)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -1106,7 +1135,7 @@ func (p *Query) SelectStmt() (localctx ISelectStmtContext) {
 			}
 		}
 		{
-			p.SetState(71)
+			p.SetState(74)
 
 			var _x = p.Ident()
 
@@ -1208,7 +1237,7 @@ func (p *Query) Clause() (localctx IClauseContext) {
 
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(74)
+		p.SetState(77)
 		_la = p.GetTokenStream().LA(1)
 
 		if !(_la == QueryCLAUSE_SAME || _la == QueryCLAUSE_DISTINCT) {
@@ -1440,7 +1469,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 	var _alt int
 
 	p.EnterOuterAlt(localctx, 1)
-	p.SetState(87)
+	p.SetState(90)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -1449,7 +1478,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 	switch p.GetTokenStream().LA(1) {
 	case QueryNOT_OP:
 		{
-			p.SetState(77)
+			p.SetState(80)
 
 			var _m = p.Match(QueryNOT_OP)
 
@@ -1460,7 +1489,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 			}
 		}
 		{
-			p.SetState(78)
+			p.SetState(81)
 			p.Match(QueryL_PAREN)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -1468,14 +1497,14 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 			}
 		}
 		{
-			p.SetState(79)
+			p.SetState(82)
 
 			var _x = p.filterExpr(0)
 
 			localctx.(*FilterExprContext).F1 = _x
 		}
 		{
-			p.SetState(80)
+			p.SetState(83)
 			p.Match(QueryR_PAREN)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -1485,7 +1514,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 
 	case QueryL_PAREN:
 		{
-			p.SetState(82)
+			p.SetState(85)
 			p.Match(QueryL_PAREN)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -1493,14 +1522,14 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 			}
 		}
 		{
-			p.SetState(83)
+			p.SetState(86)
 
 			var _x = p.filterExpr(0)
 
 			localctx.(*FilterExprContext).Inner = _x
 		}
 		{
-			p.SetState(84)
+			p.SetState(87)
 			p.Match(QueryR_PAREN)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -1510,7 +1539,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 
 	case QueryREP, QueryIN, QueryAS, QuerySELECT, QueryFROM, QueryFILTER, QueryAT, QueryIDENT, QuerySTRING:
 		{
-			p.SetState(86)
+			p.SetState(89)
 			p.Expr()
 		}
 
@@ -1519,12 +1548,12 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 		goto errorExit
 	}
 	p.GetParserRuleContext().SetStop(p.GetTokenStream().LT(-1))
-	p.SetState(97)
+	p.SetState(100)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
 	}
-	_alt = p.GetInterpreter().AdaptivePredict(p.BaseParser, p.GetTokenStream(), 10, p.GetParserRuleContext())
+	_alt = p.GetInterpreter().AdaptivePredict(p.BaseParser, p.GetTokenStream(), 11, p.GetParserRuleContext())
 	if p.HasError() {
 		goto errorExit
 	}
@@ -1534,25 +1563,25 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 				p.TriggerExitRuleEvent()
 			}
 			_prevctx = localctx
-			p.SetState(95)
+			p.SetState(98)
 			p.GetErrorHandler().Sync(p)
 			if p.HasError() {
 				goto errorExit
 			}
 
-			switch p.GetInterpreter().AdaptivePredict(p.BaseParser, p.GetTokenStream(), 9, p.GetParserRuleContext()) {
+			switch p.GetInterpreter().AdaptivePredict(p.BaseParser, p.GetTokenStream(), 10, p.GetParserRuleContext()) {
 			case 1:
 				localctx = NewFilterExprContext(p, _parentctx, _parentState)
 				localctx.(*FilterExprContext).F1 = _prevctx
 				p.PushNewRecursionContext(localctx, _startState, QueryRULE_filterExpr)
-				p.SetState(89)
+				p.SetState(92)
 
 				if !(p.Precpred(p.GetParserRuleContext(), 4)) {
 					p.SetError(antlr.NewFailedPredicateException(p, "p.Precpred(p.GetParserRuleContext(), 4)", ""))
 					goto errorExit
 				}
 				{
-					p.SetState(90)
+					p.SetState(93)
 
 					var _m = p.Match(QueryAND_OP)
 
@@ -1563,7 +1592,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 					}
 				}
 				{
-					p.SetState(91)
+					p.SetState(94)
 
 					var _x = p.filterExpr(5)
 
@@ -1574,14 +1603,14 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 				localctx = NewFilterExprContext(p, _parentctx, _parentState)
 				localctx.(*FilterExprContext).F1 = _prevctx
 				p.PushNewRecursionContext(localctx, _startState, QueryRULE_filterExpr)
-				p.SetState(92)
+				p.SetState(95)
 
 				if !(p.Precpred(p.GetParserRuleContext(), 3)) {
 					p.SetError(antlr.NewFailedPredicateException(p, "p.Precpred(p.GetParserRuleContext(), 3)", ""))
 					goto errorExit
 				}
 				{
-					p.SetState(93)
+					p.SetState(96)
 
 					var _m = p.Match(QueryOR_OP)
 
@@ -1592,7 +1621,7 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 					}
 				}
 				{
-					p.SetState(94)
+					p.SetState(97)
 
 					var _x = p.filterExpr(4)
 
@@ -1604,12 +1633,12 @@ func (p *Query) filterExpr(_p int) (localctx IFilterExprContext) {
 			}
 
 		}
-		p.SetState(99)
+		p.SetState(102)
 		p.GetErrorHandler().Sync(p)
 		if p.HasError() {
 			goto errorExit
 		}
-		_alt = p.GetInterpreter().AdaptivePredict(p.BaseParser, p.GetTokenStream(), 10, p.GetParserRuleContext())
+		_alt = p.GetInterpreter().AdaptivePredict(p.BaseParser, p.GetTokenStream(), 11, p.GetParserRuleContext())
 		if p.HasError() {
 			goto errorExit
 		}
@@ -1762,7 +1791,7 @@ func (p *Query) FilterStmt() (localctx IFilterStmtContext) {
 	p.EnterRule(localctx, 12, QueryRULE_filterStmt)
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(100)
+		p.SetState(103)
 		p.Match(QueryFILTER)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -1770,14 +1799,14 @@ func (p *Query) FilterStmt() (localctx IFilterStmtContext) {
 		}
 	}
 	{
-		p.SetState(101)
+		p.SetState(104)
 
 		var _x = p.filterExpr(0)
 
 		localctx.(*FilterStmtContext).Expr = _x
 	}
 	{
-		p.SetState(102)
+		p.SetState(105)
 		p.Match(QueryAS)
 		if p.HasError() {
 			// Recognition error - abort rule
@@ -1785,7 +1814,7 @@ func (p *Query) FilterStmt() (localctx IFilterStmtContext) {
 		}
 	}
 	{
-		p.SetState(103)
+		p.SetState(106)
 
 		var _x = p.Ident()
 
@@ -1965,7 +1994,7 @@ func (s *ExprContext) Accept(visitor antlr.ParseTreeVisitor) interface{} {
 func (p *Query) Expr() (localctx IExprContext) {
 	localctx = NewExprContext(p, p.GetParserRuleContext(), p.GetState())
 	p.EnterRule(localctx, 14, QueryRULE_expr)
-	p.SetState(111)
+	p.SetState(114)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -1975,7 +2004,7 @@ func (p *Query) Expr() (localctx IExprContext) {
 	case QueryAT:
 		p.EnterOuterAlt(localctx, 1)
 		{
-			p.SetState(105)
+			p.SetState(108)
 			p.Match(QueryAT)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -1983,7 +2012,7 @@ func (p *Query) Expr() (localctx IExprContext) {
 			}
 		}
 		{
-			p.SetState(106)
+			p.SetState(109)
 
 			var _x = p.Ident()
 
@@ -1993,14 +2022,14 @@ func (p *Query) Expr() (localctx IExprContext) {
 	case QueryREP, QueryIN, QueryAS, QuerySELECT, QueryFROM, QueryFILTER, QueryIDENT, QuerySTRING:
 		p.EnterOuterAlt(localctx, 2)
 		{
-			p.SetState(107)
+			p.SetState(110)
 
 			var _x = p.FilterKey()
 
 			localctx.(*ExprContext).Key = _x
 		}
 		{
-			p.SetState(108)
+			p.SetState(111)
 			p.Match(QuerySIMPLE_OP)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -2008,7 +2037,7 @@ func (p *Query) Expr() (localctx IExprContext) {
 			}
 		}
 		{
-			p.SetState(109)
+			p.SetState(112)
 
 			var _x = p.FilterValue()
 
@@ -2121,7 +2150,7 @@ func (s *FilterKeyContext) Accept(visitor antlr.ParseTreeVisitor) interface{} {
 func (p *Query) FilterKey() (localctx IFilterKeyContext) {
 	localctx = NewFilterKeyContext(p, p.GetParserRuleContext(), p.GetState())
 	p.EnterRule(localctx, 16, QueryRULE_filterKey)
-	p.SetState(115)
+	p.SetState(118)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -2131,14 +2160,14 @@ func (p *Query) FilterKey() (localctx IFilterKeyContext) {
 	case QueryREP, QueryIN, QueryAS, QuerySELECT, QueryFROM, QueryFILTER, QueryIDENT:
 		p.EnterOuterAlt(localctx, 1)
 		{
-			p.SetState(113)
+			p.SetState(116)
 			p.Ident()
 		}
 
 	case QuerySTRING:
 		p.EnterOuterAlt(localctx, 2)
 		{
-			p.SetState(114)
+			p.SetState(117)
 			p.Match(QuerySTRING)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -2269,7 +2298,7 @@ func (s *FilterValueContext) Accept(visitor antlr.ParseTreeVisitor) interface{}
 func (p *Query) FilterValue() (localctx IFilterValueContext) {
 	localctx = NewFilterValueContext(p, p.GetParserRuleContext(), p.GetState())
 	p.EnterRule(localctx, 18, QueryRULE_filterValue)
-	p.SetState(120)
+	p.SetState(123)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -2279,21 +2308,21 @@ func (p *Query) FilterValue() (localctx IFilterValueContext) {
 	case QueryREP, QueryIN, QueryAS, QuerySELECT, QueryFROM, QueryFILTER, QueryIDENT:
 		p.EnterOuterAlt(localctx, 1)
 		{
-			p.SetState(117)
+			p.SetState(120)
 			p.Ident()
 		}
 
 	case QueryNUMBER1, QueryZERO:
 		p.EnterOuterAlt(localctx, 2)
 		{
-			p.SetState(118)
+			p.SetState(121)
 			p.Number()
 		}
 
 	case QuerySTRING:
 		p.EnterOuterAlt(localctx, 3)
 		{
-			p.SetState(119)
+			p.SetState(122)
 			p.Match(QuerySTRING)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -2399,7 +2428,7 @@ func (p *Query) Number() (localctx INumberContext) {
 
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(122)
+		p.SetState(125)
 		_la = p.GetTokenStream().LA(1)
 
 		if !(_la == QueryNUMBER1 || _la == QueryZERO) {
@@ -2523,10 +2552,10 @@ func (p *Query) Keyword() (localctx IKeywordContext) {
 
 	p.EnterOuterAlt(localctx, 1)
 	{
-		p.SetState(124)
+		p.SetState(127)
 		_la = p.GetTokenStream().LA(1)
 
-		if !((int64(_la) & ^0x3f) == 0 && ((int64(1)<<_la)&3808) != 0) {
+		if !((int64(_la) & ^0x3f) == 0 && ((int64(1)<<_la)&7616) != 0) {
 			p.GetErrorHandler().RecoverInline(p)
 		} else {
 			p.GetErrorHandler().ReportMatch(p)
@@ -2635,7 +2664,7 @@ func (s *IdentContext) Accept(visitor antlr.ParseTreeVisitor) interface{} {
 func (p *Query) Ident() (localctx IIdentContext) {
 	localctx = NewIdentContext(p, p.GetParserRuleContext(), p.GetState())
 	p.EnterRule(localctx, 24, QueryRULE_ident)
-	p.SetState(128)
+	p.SetState(131)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -2645,14 +2674,14 @@ func (p *Query) Ident() (localctx IIdentContext) {
 	case QueryREP, QueryIN, QueryAS, QuerySELECT, QueryFROM, QueryFILTER:
 		p.EnterOuterAlt(localctx, 1)
 		{
-			p.SetState(126)
+			p.SetState(129)
 			p.Keyword()
 		}
 
 	case QueryIDENT:
 		p.EnterOuterAlt(localctx, 2)
 		{
-			p.SetState(127)
+			p.SetState(130)
 			p.Match(QueryIDENT)
 			if p.HasError() {
 				// Recognition error - abort rule
@@ -2766,7 +2795,7 @@ func (s *IdentWCContext) Accept(visitor antlr.ParseTreeVisitor) interface{} {
 func (p *Query) IdentWC() (localctx IIdentWCContext) {
 	localctx = NewIdentWCContext(p, p.GetParserRuleContext(), p.GetState())
 	p.EnterRule(localctx, 26, QueryRULE_identWC)
-	p.SetState(132)
+	p.SetState(135)
 	p.GetErrorHandler().Sync(p)
 	if p.HasError() {
 		goto errorExit
@@ -2776,14 +2805,14 @@ func (p *Query) IdentWC() (localctx IIdentWCContext) {
 	case QueryREP, QueryIN, QueryAS, QuerySELECT, QueryFROM, QueryFILTER, QueryIDENT:
 		p.EnterOuterAlt(localctx, 1)
 		{
-			p.SetState(130)
+			p.SetState(133)
 			p.Ident()
 		}
 
 	case QueryWILDCARD:
 		p.EnterOuterAlt(localctx, 2)
 		{
-			p.SetState(131)
+			p.SetState(134)
 			p.Match(QueryWILDCARD)
 			if p.HasError() {
 				// Recognition error - abort rule
diff --git a/netmap/parser/query_visitor.go b/netmap/parser/query_visitor.go
index 8123c39..960dc2f 100644
--- a/netmap/parser/query_visitor.go
+++ b/netmap/parser/query_visitor.go
@@ -1,3 +1,5 @@
+// Code generated from Query.g4 by ANTLR 4.13.0. DO NOT EDIT.
+
 package parser // Query
 
 import "github.com/antlr4-go/antlr/v4"
diff --git a/netmap/policy.go b/netmap/policy.go
index 3f6986e..a03d36e 100644
--- a/netmap/policy.go
+++ b/netmap/policy.go
@@ -28,6 +28,8 @@ type PlacementPolicy struct {
 	selectors []netmap.Selector
 
 	replicas []netmap.Replica
+
+	unique bool
 }
 
 func (p *PlacementPolicy) readFromV2(m netmap.PlacementPolicy, checkFieldPresence bool) error {
@@ -39,6 +41,7 @@ func (p *PlacementPolicy) readFromV2(m netmap.PlacementPolicy, checkFieldPresenc
 	p.backupFactor = m.GetContainerBackupFactor()
 	p.selectors = m.GetSelectors()
 	p.filters = m.GetFilters()
+	p.unique = m.GetUnique()
 
 	return nil
 }
@@ -113,6 +116,7 @@ func (p PlacementPolicy) WriteToV2(m *netmap.PlacementPolicy) {
 	m.SetFilters(p.filters)
 	m.SetSelectors(p.selectors)
 	m.SetReplicas(p.replicas)
+	m.SetUnique(p.unique)
 }
 
 // ReplicaDescriptor replica descriptor characterizes replicas of objects from
@@ -178,6 +182,14 @@ func (p *PlacementPolicy) SetContainerBackupFactor(f uint32) {
 	p.backupFactor = f
 }
 
+// SetUnique sets the unique flag: it controls whether the selected replica buckets
+// are disjoint or not.
+//
+// Zero PlacementPolicy has false unique flag.
+func (p *PlacementPolicy) SetUnique(b bool) {
+	p.unique = b
+}
+
 // Selector describes the bucket selection operator: choose a number of nodes
 // from the bucket taking the nearest nodes to the related container by hash distance.
 type Selector struct {
@@ -363,6 +375,12 @@ func (p *PlacementPolicy) AddFilters(fs ...Filter) {
 //
 // See also DecodeString.
 func (p PlacementPolicy) WriteStringTo(w io.StringWriter) (err error) {
+	if p.unique {
+		if _, err := w.WriteString("UNIQUE\n"); err != nil {
+			return err
+		}
+	}
+
 	delim := ""
 
 	for i := range p.replicas {
@@ -572,6 +590,9 @@ func (p *policyVisitor) VisitPolicy(ctx *parser.PolicyContext) any {
 	}
 
 	pl := new(PlacementPolicy)
+
+	pl.unique = ctx.UNIQUE() != nil
+
 	repStmts := ctx.AllRepStmt()
 	pl.replicas = make([]netmap.Replica, 0, len(repStmts))
 
diff --git a/netmap/policy_test.go b/netmap/policy_test.go
index f0a7bc5..75167dc 100644
--- a/netmap/policy_test.go
+++ b/netmap/policy_test.go
@@ -27,6 +27,10 @@ FILTER City EQ SPB AND SSD EQ true OR City EQ SPB AND Rating GE 5 AS SPBSSD`,
 		`REP 7 IN SPB
 SELECT 1 IN City FROM SPBSSD AS SPB
 FILTER NOT (NOT (City EQ SPB) AND SSD EQ true OR City EQ SPB AND Rating GE 5) AS SPBSSD`,
+
+		`UNIQUE
+REP 1
+REP 1`,
 	}
 
 	var p PlacementPolicy
diff --git a/netmap/selector.go b/netmap/selector.go
index 51ceb47..d8c767a 100644
--- a/netmap/selector.go
+++ b/netmap/selector.go
@@ -140,6 +140,9 @@ func (c *context) getSelectionBase(s netmap.Selector) []nodeAttrPair {
 	attr := s.GetAttribute()
 
 	for i := range c.netMap.nodes {
+		if c.usedNodes[c.netMap.nodes[i].hash] {
+			continue
+		}
 		if isMain || c.match(f, c.netMap.nodes[i]) {
 			if attr == "" {
 				// Default attribute is transparent identifier which is different for every node.
diff --git a/netmap/selector_test.go b/netmap/selector_test.go
index a974852..a80d922 100644
--- a/netmap/selector_test.go
+++ b/netmap/selector_test.go
@@ -1,6 +1,7 @@
 package netmap
 
 import (
+	"encoding/binary"
 	"fmt"
 	"math/rand"
 	"sort"
@@ -244,6 +245,43 @@ func TestPlacementPolicy_ProcessSelectors(t *testing.T) {
 	}
 }
 
+func TestPlacementPolicy_Unique(t *testing.T) {
+	p := newPlacementPolicy(2,
+		[]ReplicaDescriptor{
+			newReplica(1, "S"),
+			newReplica(1, "S"),
+		},
+		[]Selector{
+			newSelector("S", "City", 1, "*", (*Selector).SelectSame),
+		},
+		[]Filter{})
+	p.unique = true
+
+	var nodes []NodeInfo
+	for i, city := range []string{"Moscow", "Berlin", "Shenzhen"} {
+		for j := 0; j < 3; j++ {
+			node := nodeInfoFromAttributes("City", city)
+			node.SetPublicKey(binary.BigEndian.AppendUint16(nil, uint16(i*4+j)))
+			nodes = append(nodes, node)
+		}
+	}
+
+	var nm NetMap
+	nm.SetNodes(nodes)
+
+	v, err := nm.ContainerNodes(p, nil)
+	require.NoError(t, err)
+	for i, vi := range v {
+		for _, ni := range vi {
+			for j := 0; j < i; j++ {
+				for _, nj := range v[j] {
+					require.NotEqual(t, ni.hash, nj.hash)
+				}
+			}
+		}
+	}
+}
+
 func TestPlacementPolicy_ProcessSelectorsExceptForNodes(t *testing.T) {
 	p := newPlacementPolicy(1, nil,
 		[]Selector{