hints

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Hints

Optimizer/Index/Comment Hints support for GORM

Optimizer Hints

import "gorm.io/hints"

DB.Clauses(hints.New("hint")).Find(&User{})
// SELECT * /*+ hint */ FROM `users`

Index Hints

import "gorm.io/hints"

DB.Clauses(hints.UseIndex("idx_user_name")).Find(&User{})
// SELECT * FROM `users` USE INDEX (`idx_user_name`)

DB.Clauses(hints.ForceIndex("idx_user_name", "idx_user_id").ForJoin()).Find(&User{})
// SELECT * FROM `users` FORCE INDEX FOR JOIN (`idx_user_name`,`idx_user_id`)"

DB.Clauses(
	hints.ForceIndex("idx_user_name", "idx_user_id").ForOrderBy(),
	hints.IgnoreIndex("idx_user_name").ForGroupBy(),
).Find(&User{})
// SELECT * FROM `users` FORCE INDEX FOR ORDER BY (`idx_user_name`,`idx_user_id`) IGNORE INDEX FOR GROUP BY (`idx_user_name`)"

Comment Hints

import "gorm.io/hints"

DB.Clauses(hints.Comment("select", "master")).Find(&User{})
// SELECT /*master*/ * FROM `users`;

DB.Clauses(hints.CommentBefore("insert", "node2")).Create(&user)
// /*node2*/ INSERT INTO `users` ...;

DB.Clauses(hints.CommentAfter("select", "node2")).Create(&user)
// /*node2*/ INSERT INTO `users` ...;

DB.Clauses(hints.CommentAfter("where", "hint")).Find(&User{}, "id = ?", 1)
// SELECT * FROM `users` WHERE id = ? /* hint */

Documentation

Index

• func IndexHintFromClauseBuilder(c clause.Clause, builder clause.Builder)
• type Exprs
  • func (exprs Exprs) Build(builder clause.Builder)
• type Hints
  • func Comment(clause string, comment string) Hints
  • func CommentAfter(clause string, comment string) Hints
  • func CommentBefore(clause string, comment string) Hints
  • func New(content string) Hints
  • func (hints Hints) Build(builder clause.Builder)
  • func (hints *Hints) Merge(h Hints)
  • func (hints Hints) ModifyStatement(stmt *gorm.Statement)
• type IndexHint
  • func ForceIndex(names ...string) IndexHint
  • func IgnoreIndex(names ...string) IndexHint
  • func UseIndex(names ...string) IndexHint
  • func (indexHint IndexHint) Build(builder clause.Builder)
  • func (indexHint IndexHint) ForGroupBy() IndexHint
  • func (indexHint IndexHint) ForJoin() IndexHint
  • func (indexHint IndexHint) ForOrderBy() IndexHint
  • func (indexHint IndexHint) ModifyStatement(stmt *gorm.Statement)

Functions

func IndexHintFromClauseBuilder

func IndexHintFromClauseBuilder(c clause.Clause, builder clause.Builder)

Types

type Exprs

type Exprs []clause.Expression

func (Exprs) Build

func (exprs Exprs) Build(builder clause.Builder)

type Hints

type Hints struct {
	Prefix  string
	Suffix  string
	Content string
	// contains filtered or unexported fields
}

func Comment

func Comment(clause string, comment string) Hints

func CommentAfter

func CommentAfter(clause string, comment string) Hints

func CommentBefore

func CommentBefore(clause string, comment string) Hints

func New

func New(content string) Hints

func (Hints) Build

func (hints Hints) Build(builder clause.Builder)

func (*Hints) Merge

func (hints *Hints) Merge(h Hints)

func (Hints) ModifyStatement

func (hints Hints) ModifyStatement(stmt *gorm.Statement)

type IndexHint

type IndexHint struct {
	Type string
	Keys []string
}

func ForceIndex

func ForceIndex(names ...string) IndexHint

func IgnoreIndex

func IgnoreIndex(names ...string) IndexHint

func UseIndex

func UseIndex(names ...string) IndexHint

func (IndexHint) Build

func (indexHint IndexHint) Build(builder clause.Builder)

func (IndexHint) ForGroupBy

func (indexHint IndexHint) ForGroupBy() IndexHint

func (IndexHint) ForJoin

func (indexHint IndexHint) ForJoin() IndexHint

func (IndexHint) ForOrderBy

func (indexHint IndexHint) ForOrderBy() IndexHint

func (IndexHint) ModifyStatement

func (indexHint IndexHint) ModifyStatement(stmt *gorm.Statement)