536 lines
14 KiB
Go
536 lines
14 KiB
Go
/*
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Copyright 2017 Google Inc. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package spanner_test
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import (
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"errors"
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"fmt"
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"time"
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"cloud.google.com/go/spanner"
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"golang.org/x/net/context"
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"google.golang.org/api/iterator"
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sppb "google.golang.org/genproto/googleapis/spanner/v1"
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)
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func ExampleNewClient() {
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ctx := context.Background()
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const myDB = "projects/my-project/instances/my-instance/database/my-db"
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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_ = client // TODO: Use client.
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}
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const myDB = "projects/my-project/instances/my-instance/database/my-db"
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func ExampleNewClientWithConfig() {
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ctx := context.Background()
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const myDB = "projects/my-project/instances/my-instance/database/my-db"
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client, err := spanner.NewClientWithConfig(ctx, myDB, spanner.ClientConfig{
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NumChannels: 10,
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})
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if err != nil {
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// TODO: Handle error.
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}
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_ = client // TODO: Use client.
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client.Close() // Close client when done.
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}
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func ExampleClient_Single() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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iter := client.Single().Query(ctx, spanner.NewStatement("SELECT FirstName FROM Singers"))
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_ = iter // TODO: iterate using Next or Do.
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}
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func ExampleClient_ReadOnlyTransaction() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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t := client.ReadOnlyTransaction()
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defer t.Close()
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// TODO: Read with t using Read, ReadRow, ReadUsingIndex, or Query.
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}
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func ExampleClient_ReadWriteTransaction() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
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var balance int64
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row, err := txn.ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"balance"})
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if err != nil {
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// This function will be called again if this is an
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// IsAborted error.
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return err
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}
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if err := row.Column(0, &balance); err != nil {
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return err
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}
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if balance <= 10 {
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return errors.New("insufficient funds in account")
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}
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balance -= 10
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m := spanner.Update("Accounts", []string{"user", "balance"}, []interface{}{"alice", balance})
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return txn.BufferWrite([]*spanner.Mutation{m})
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// The buffered mutation will be committed. If the commit
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// fails with an IsAborted error, this function will be called
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// again.
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})
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if err != nil {
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// TODO: Handle error.
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}
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}
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func ExampleUpdate() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
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row, err := txn.ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"balance"})
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if err != nil {
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return err
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}
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var balance int64
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if err := row.Column(0, &balance); err != nil {
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return err
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}
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return txn.BufferWrite([]*spanner.Mutation{
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spanner.Update("Accounts", []string{"user", "balance"}, []interface{}{"alice", balance + 10}),
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})
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})
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if err != nil {
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// TODO: Handle error.
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}
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}
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// This example is the same as the one for Update, except for the use of UpdateMap.
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func ExampleUpdateMap() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
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row, err := txn.ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"balance"})
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if err != nil {
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return err
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}
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var balance int64
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if err := row.Column(0, &balance); err != nil {
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return err
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}
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return txn.BufferWrite([]*spanner.Mutation{
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spanner.UpdateMap("Accounts", map[string]interface{}{
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"user": "alice",
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"balance": balance + 10,
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}),
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})
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})
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if err != nil {
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// TODO: Handle error.
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}
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}
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// This example is the same as the one for Update, except for the use of UpdateStruct.
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func ExampleUpdateStruct() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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type account struct {
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User string `spanner:"user"`
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Balance int64 `spanner:"balance"`
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}
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_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
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row, err := txn.ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"balance"})
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if err != nil {
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return err
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}
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var balance int64
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if err := row.Column(0, &balance); err != nil {
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return err
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}
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m, err := spanner.UpdateStruct("Accounts", account{
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User: "alice",
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Balance: balance + 10,
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})
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if err != nil {
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return err
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}
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return txn.BufferWrite([]*spanner.Mutation{m})
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})
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if err != nil {
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// TODO: Handle error.
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}
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}
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func ExampleClient_Apply() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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m := spanner.Update("Users", []string{"name", "email"}, []interface{}{"alice", "a@example.com"})
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_, err = client.Apply(ctx, []*spanner.Mutation{m})
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if err != nil {
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// TODO: Handle error.
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}
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}
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func ExampleInsert() {
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m := spanner.Insert("Users", []string{"name", "email"}, []interface{}{"alice", "a@example.com"})
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_ = m // TODO: use with Client.Apply or in a ReadWriteTransaction.
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}
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func ExampleInsertMap() {
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m := spanner.InsertMap("Users", map[string]interface{}{
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"name": "alice",
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"email": "a@example.com",
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})
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_ = m // TODO: use with Client.Apply or in a ReadWriteTransaction.
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}
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func ExampleInsertStruct() {
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type User struct {
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Name, Email string
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}
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u := User{Name: "alice", Email: "a@example.com"}
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m, err := spanner.InsertStruct("Users", u)
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if err != nil {
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// TODO: Handle error.
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}
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_ = m // TODO: use with Client.Apply or in a ReadWriteTransaction.
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}
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func ExampleDelete() {
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m := spanner.Delete("Users", spanner.Key{"alice"})
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_ = m // TODO: use with Client.Apply or in a ReadWriteTransaction.
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}
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func ExampleDelete_keyRange() {
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m := spanner.Delete("Users", spanner.KeyRange{
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Start: spanner.Key{"alice"},
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End: spanner.Key{"bob"},
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Kind: spanner.ClosedClosed,
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})
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_ = m // TODO: use with Client.Apply or in a ReadWriteTransaction.
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}
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func ExampleRowIterator_Next() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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iter := client.Single().Query(ctx, spanner.NewStatement("SELECT FirstName FROM Singers"))
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defer iter.Stop()
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for {
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row, err := iter.Next()
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if err == iterator.Done {
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break
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}
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if err != nil {
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// TODO: Handle error.
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}
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var firstName string
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if err := row.Column(0, &firstName); err != nil {
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// TODO: Handle error.
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}
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fmt.Println(firstName)
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}
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}
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func ExampleRowIterator_Do() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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iter := client.Single().Query(ctx, spanner.NewStatement("SELECT FirstName FROM Singers"))
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err = iter.Do(func(r *spanner.Row) error {
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var firstName string
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if err := r.Column(0, &firstName); err != nil {
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return err
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}
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fmt.Println(firstName)
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return nil
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})
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if err != nil {
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// TODO: Handle error.
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}
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}
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func ExampleRow_Size() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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fmt.Println(row.Size()) // size is 2
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}
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func ExampleRow_ColumnName() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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fmt.Println(row.ColumnName(1)) // prints "balance"
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}
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func ExampleRow_ColumnIndex() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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index, err := row.ColumnIndex("balance")
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if err != nil {
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// TODO: Handle error.
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}
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fmt.Println(index)
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}
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func ExampleRow_ColumnNames() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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fmt.Println(row.ColumnNames())
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}
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func ExampleRow_ColumnByName() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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var balance int64
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if err := row.ColumnByName("balance", &balance); err != nil {
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// TODO: Handle error.
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}
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fmt.Println(balance)
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}
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func ExampleRow_Columns() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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var name string
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var balance int64
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if err := row.Columns(&name, &balance); err != nil {
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// TODO: Handle error.
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}
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fmt.Println(name, balance)
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}
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func ExampleRow_ToStruct() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Accounts", spanner.Key{"alice"}, []string{"name", "balance"})
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if err != nil {
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// TODO: Handle error.
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}
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type Account struct {
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Name string
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Balance int64
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}
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var acct Account
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if err := row.ToStruct(&acct); err != nil {
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// TODO: Handle error.
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}
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fmt.Println(acct)
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}
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func ExampleReadOnlyTransaction_Read() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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iter := client.Single().Read(ctx, "Users",
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spanner.KeySets(spanner.Key{"alice"}, spanner.Key{"bob"}),
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[]string{"name", "email"})
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_ = iter // TODO: iterate using Next or Do.
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}
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func ExampleReadOnlyTransaction_ReadUsingIndex() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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iter := client.Single().ReadUsingIndex(ctx, "Users",
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"UsersByEmail",
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spanner.KeySets(spanner.Key{"a@example.com"}, spanner.Key{"b@example.com"}),
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[]string{"name", "email"})
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_ = iter // TODO: iterate using Next or Do.
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}
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func ExampleReadOnlyTransaction_ReadRow() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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row, err := client.Single().ReadRow(ctx, "Users", spanner.Key{"alice"},
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[]string{"name", "email"})
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if err != nil {
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// TODO: Handle error.
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}
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_ = row // TODO: use row
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}
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func ExampleReadOnlyTransaction_Query() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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iter := client.Single().Query(ctx, spanner.NewStatement("SELECT FirstName FROM Singers"))
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_ = iter // TODO: iterate using Next or Do.
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}
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func ExampleNewStatement() {
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stmt := spanner.NewStatement("SELECT FirstName, LastName FROM SINGERS WHERE LastName >= @start")
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stmt.Params["start"] = "Dylan"
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// TODO: Use stmt in Query.
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}
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func ExampleNewStatement_structLiteral() {
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stmt := spanner.Statement{
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SQL: "SELECT FirstName, LastName FROM SINGERS WHERE LastName >= @start",
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Params: map[string]interface{}{"start": "Dylan"},
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}
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_ = stmt // TODO: Use stmt in Query.
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}
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func ExampleReadOnlyTransaction_Timestamp() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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txn := client.Single()
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row, err := txn.ReadRow(ctx, "Users", spanner.Key{"alice"},
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[]string{"name", "email"})
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if err != nil {
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// TODO: Handle error.
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}
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readTimestamp, err := txn.Timestamp()
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if err != nil {
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// TODO: Handle error.
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}
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fmt.Println("read happened at", readTimestamp)
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_ = row // TODO: use row
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}
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func ExampleReadOnlyTransaction_WithTimestampBound() {
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ctx := context.Background()
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client, err := spanner.NewClient(ctx, myDB)
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if err != nil {
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// TODO: Handle error.
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}
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txn := client.Single().WithTimestampBound(spanner.MaxStaleness(30 * time.Second))
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row, err := txn.ReadRow(ctx, "Users", spanner.Key{"alice"}, []string{"name", "email"})
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if err != nil {
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// TODO: Handle error.
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}
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_ = row // TODO: use row
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readTimestamp, err := txn.Timestamp()
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if err != nil {
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// TODO: Handle error.
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}
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fmt.Println("read happened at", readTimestamp)
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}
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func ExampleGenericColumnValue_Decode() {
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// In real applications, rows can be retrieved by methods like client.Single().ReadRow().
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row, err := spanner.NewRow([]string{"intCol", "strCol"}, []interface{}{42, "my-text"})
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if err != nil {
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// TODO: Handle error.
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}
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for i := 0; i < row.Size(); i++ {
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var col spanner.GenericColumnValue
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if err := row.Column(i, &col); err != nil {
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// TODO: Handle error.
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}
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switch col.Type.Code {
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case sppb.TypeCode_INT64:
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var v int64
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if err := col.Decode(&v); err != nil {
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// TODO: Handle error.
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}
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fmt.Println("int", v)
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case sppb.TypeCode_STRING:
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var v string
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if err := col.Decode(&v); err != nil {
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// TODO: Handle error.
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}
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fmt.Println("string", v)
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}
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}
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// Output:
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// int 42
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// string my-text
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}
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