stmt/stmts: add back deleted file to make it easier to review.
This commit is contained in:
Ewan Chou
234
stmt/stmts/prepared.go
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234
stmt/stmts/prepared.go
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// Copyright 2015 PingCAP, Inc.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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// See the License for the specific language governing permissions and
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// limitations under the License.
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package stmts
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import (
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"fmt"
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"strings"
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"github.com/juju/errors"
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"github.com/pingcap/tidb/context"
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"github.com/pingcap/tidb/expression"
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"github.com/pingcap/tidb/field"
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"github.com/pingcap/tidb/rset"
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"github.com/pingcap/tidb/sessionctx/variable"
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"github.com/pingcap/tidb/stmt"
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"github.com/pingcap/tidb/util/format"
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)
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var (
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_ stmt.Statement = (*PreparedStmt)(nil)
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_ stmt.Statement = (*DeallocateStmt)(nil)
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_ stmt.Statement = (*ExecuteStmt)(nil)
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)
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// PreparedStmt is a statement to prepares a SQL statement which contains placeholders,
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// and it is executed with ExecuteStmt and released with DeallocateStmt.
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// See: https://dev.mysql.com/doc/refman/5.7/en/prepare.html
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type PreparedStmt struct {
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InPrepare bool // true for prepare mode, false for use mode
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Name string
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ID uint32 // For binary protocol, there is no Name but only ID
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SQLText string
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SQLVar *expression.Variable
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SQLStmt stmt.Statement // The parsed statement from sql text with placeholder
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Params []*expression.ParamMarker
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Fields []*field.ResultField
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Text string
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}
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// Explain implements the stmt.Statement Explain interface.
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func (s *PreparedStmt) Explain(ctx context.Context, w format.Formatter) {
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w.Format("%s\n", s.Text)
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}
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// IsDDL implements the stmt.Statement IsDDL interface.
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func (s *PreparedStmt) IsDDL() bool {
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return false
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}
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// OriginText implements the stmt.Statement OriginText interface.
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func (s *PreparedStmt) OriginText() string {
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return s.Text
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}
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// SetText implements the stmt.Statement SetText interface.
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func (s *PreparedStmt) SetText(text string) {
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s.Text = text
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}
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func getPreparedStmtIDKey(id uint32) string {
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return fmt.Sprintf("%d", id)
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}
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// Exec implements the stmt.Statement Exec interface.
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func (s *PreparedStmt) Exec(ctx context.Context) (_ rset.Recordset, err error) {
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if !s.InPrepare {
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// Can not execute a prepared statement in use status.
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// TODO: this is an error?
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return nil, nil
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}
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err = s.checkPreparedStmt(ctx)
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if err != nil {
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return nil, err
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}
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vars := variable.GetSessionVars(ctx)
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if len(s.Name) == 0 {
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s.ID = vars.GetNextPreparedStmtID()
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s.Name = getPreparedStmtIDKey(s.ID)
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}
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return nil, nil
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}
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// GetSQL get prepared SQL text.
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func (s *PreparedStmt) GetSQL(ctx context.Context) (string, error) {
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// TODO: finish this.
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if s.SQLVar == nil {
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return s.SQLText, nil
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}
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// Get var value.
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vars := variable.GetSessionVars(ctx)
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name := strings.ToLower(s.SQLVar.Name)
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sql, ok := vars.Users[name]
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if !ok {
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// TODO: cannot find use var, return error?
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return "", nil
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}
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return sql, nil
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}
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// checkPreparedStmt checks prepared statement validity.
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func (s *PreparedStmt) checkPreparedStmt(ctx context.Context) error {
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if s.SQLStmt == nil {
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return errors.New("Empty prepared statement")
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}
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switch x := s.SQLStmt.(type) {
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case *SelectStmt:
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return s.checkSelect(ctx, x)
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default:
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return nil
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}
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}
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func (s *PreparedStmt) checkSelect(ctx context.Context, ss *SelectStmt) error {
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_, err := ss.Plan(ctx)
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return err
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}
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// DeallocateStmt is a statement to release PreparedStmt.
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// See: https://dev.mysql.com/doc/refman/5.7/en/deallocate-prepare.html
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type DeallocateStmt struct {
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Name string
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ID uint32 // For binary protocol, there is no Name but only ID.
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Text string
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}
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// Explain implements the stmt.Statement Explain interface.
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func (s *DeallocateStmt) Explain(ctx context.Context, w format.Formatter) {
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w.Format("%s\n", s.Text)
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}
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// IsDDL implements the stmt.Statement IsDDL interface.
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func (s *DeallocateStmt) IsDDL() bool {
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return false
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}
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// OriginText implements the stmt.Statement OriginText interface.
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func (s *DeallocateStmt) OriginText() string {
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return s.Text
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}
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// SetText implements the stmt.Statement SetText interface.
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func (s *DeallocateStmt) SetText(text string) {
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s.Text = text
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}
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// Exec implements the stmt.Statement Exec interface.
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func (s *DeallocateStmt) Exec(ctx context.Context) (_ rset.Recordset, err error) {
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// Get prepared statement.
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vars := variable.GetSessionVars(ctx)
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if len(s.Name) == 0 {
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s.Name = getPreparedStmtIDKey(s.ID)
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}
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_, ok := vars.PreparedStmts[0]
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if !ok {
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return nil, errors.Errorf("Can not find prepared statement with name %s", s.Name)
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}
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delete(vars.PreparedStmts, 0)
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return nil, nil
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}
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// ExecuteStmt is a statement to execute PreparedStmt.
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// See: https://dev.mysql.com/doc/refman/5.7/en/execute.html
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type ExecuteStmt struct {
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Name string
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ID uint32 // For binary protocol, there is no Name but only ID
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UsingVars []expression.Expression
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Text string
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}
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// Explain implements the stmt.Statement Explain interface.
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func (s *ExecuteStmt) Explain(ctx context.Context, w format.Formatter) {
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w.Format("%s\n", s.Text)
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}
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// IsDDL implements the stmt.Statement IsDDL interface.
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func (s *ExecuteStmt) IsDDL() bool {
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return false
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}
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// OriginText implements the stmt.Statement OriginText interface.
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func (s *ExecuteStmt) OriginText() string {
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return s.Text
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}
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// SetText implements the stmt.Statement SetText interface.
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func (s *ExecuteStmt) SetText(text string) {
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s.Text = text
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}
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// Exec implements the stmt.Statement Exec interface.
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func (s *ExecuteStmt) Exec(ctx context.Context) (_ rset.Recordset, err error) {
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// Get prepared statement.
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vars := variable.GetSessionVars(ctx)
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if len(s.Name) == 0 {
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s.Name = getPreparedStmtIDKey(s.ID)
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}
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vs, ok := vars.PreparedStmts[0]
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if !ok {
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return nil, errors.Errorf("Can not find prepared statement with name %s", s.Name)
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}
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ps, ok := vs.(*PreparedStmt)
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if !ok {
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return nil, errors.Errorf("Statement %s is not PreparedStmt, but %T", s.Name, vs)
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}
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// Fill param markers.
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if len(s.UsingVars) != len(ps.Params) {
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return nil, errors.Errorf("Parameter number does not match between prepared statement(%d) and execute statement(%d)", len(ps.Params), len(s.UsingVars))
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}
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for i, v := range s.UsingVars {
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ps.Params[i].Expr = v
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}
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ps.InPrepare = false
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// Run statement.
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return ps.SQLStmt.Exec(ctx)
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}
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