*: add IF EXISTS and IF NOT EXISTS supported for MariaDB (#337)

pingcap · Jun 13, 2019 · d2cf607 · d2cf607
1 parent 3b36f86
commit d2cf607
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Showing 4 changed files with 2,436 additions and 2,327 deletions.
diff --git a/ast/ddl.go b/ast/ddl.go
@@ -568,6 +568,10 @@ const (
 type Constraint struct {
 	node
 
+	// only supported by MariaDB 10.0.2+ (ADD {INDEX|KEY}, ADD FOREIGN KEY),
+	// see https://mariadb.com/kb/en/library/alter-table/
+	IfNotExists bool
+
 	Tp   ConstraintType
 	Name string
 
@@ -587,8 +591,14 @@ func (n *Constraint) Restore(ctx *RestoreCtx) error {
 		ctx.WriteKeyWord("PRIMARY KEY")
 	case ConstraintKey:
 		ctx.WriteKeyWord("KEY")
+		if n.IfNotExists {
+			ctx.WriteKeyWord(" IF NOT EXISTS")
+		}
 	case ConstraintIndex:
 		ctx.WriteKeyWord("INDEX")
+		if n.IfNotExists {
+			ctx.WriteKeyWord(" IF NOT EXISTS")
+		}
 	case ConstraintUniq:
 		ctx.WriteKeyWord("UNIQUE")
 	case ConstraintUniqKey:
@@ -606,6 +616,9 @@ func (n *Constraint) Restore(ctx *RestoreCtx) error {
 			ctx.WritePlain(" ")
 		}
 		ctx.WriteKeyWord("FOREIGN KEY ")
+		if n.IfNotExists {
+			ctx.WriteKeyWord("IF NOT EXISTS ")
+		}
 	} else if n.Name != "" {
 		ctx.WritePlain(" ")
 		ctx.WriteName(n.Name)
@@ -1120,6 +1133,10 @@ func (n *CreateViewStmt) Accept(v Visitor) (Node, bool) {
 type CreateIndexStmt struct {
 	ddlNode
 
+	// only supported by MariaDB 10.0.2+,
+	// see https://mariadb.com/kb/en/library/create-index/
+	IfNotExists bool
+
 	IndexName     string
 	Table         *TableName
 	Unique        bool
@@ -1134,6 +1151,9 @@ func (n *CreateIndexStmt) Restore(ctx *RestoreCtx) error {
 		ctx.WriteKeyWord("UNIQUE ")
 	}
 	ctx.WriteKeyWord("INDEX ")
+	if n.IfNotExists {
+		ctx.WriteKeyWord("IF NOT EXISTS ")
+	}
 	ctx.WriteName(n.IndexName)
 	ctx.WriteKeyWord(" ON ")
 	if err := n.Table.Restore(ctx); err != nil {
@@ -1641,6 +1661,14 @@ func (a AlterAlgorithm) String() string {
 type AlterTableSpec struct {
 	node
 
+	// only supported by MariaDB 10.0.2+ (DROP COLUMN, CHANGE COLUMN, MODIFY COLUMN, DROP INDEX, DROP FOREIGN KEY, DROP PARTITION)
+	// see https://mariadb.com/kb/en/library/alter-table/
+	IfExists bool
+
+	// only supported by MariaDB 10.0.2+ (ADD COLUMN, ADD PARTITION)
+	// see https://mariadb.com/kb/en/library/alter-table/
+	IfNotExists bool
+
 	Tp              AlterTableType
 	Name            string
 	Constraint      *Constraint
@@ -1684,6 +1712,9 @@ func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 		}
 	case AlterTableAddColumns:
 		ctx.WriteKeyWord("ADD COLUMN ")
+		if n.IfNotExists {
+			ctx.WriteKeyWord("IF NOT EXISTS ")
+		}
 		if n.Position != nil && len(n.NewColumns) == 1 {
 			if err := n.NewColumns[0].Restore(ctx); err != nil {
 				return errors.Annotatef(err, "An error occurred while restore AlterTableSpec.NewColumns[%d]", 0)
@@ -1713,6 +1744,9 @@ func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 		}
 	case AlterTableDropColumn:
 		ctx.WriteKeyWord("DROP COLUMN ")
+		if n.IfExists {
+			ctx.WriteKeyWord("IF EXISTS ")
+		}
 		if err := n.OldColumnName.Restore(ctx); err != nil {
 			return errors.Annotate(err, "An error occurred while restore AlterTableSpec.OldColumnName")
 		}
@@ -1721,12 +1755,21 @@ func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 		ctx.WriteKeyWord("DROP PRIMARY KEY")
 	case AlterTableDropIndex:
 		ctx.WriteKeyWord("DROP INDEX ")
+		if n.IfExists {
+			ctx.WriteKeyWord("IF EXISTS ")
+		}
 		ctx.WriteName(n.Name)
 	case AlterTableDropForeignKey:
 		ctx.WriteKeyWord("DROP FOREIGN KEY ")
+		if n.IfExists {
+			ctx.WriteKeyWord("IF EXISTS ")
+		}
 		ctx.WriteName(n.Name)
 	case AlterTableModifyColumn:
 		ctx.WriteKeyWord("MODIFY COLUMN ")
+		if n.IfExists {
+			ctx.WriteKeyWord("IF EXISTS ")
+		}
 		if err := n.NewColumns[0].Restore(ctx); err != nil {
 			return errors.Annotate(err, "An error occurred while restore AlterTableSpec.NewColumns[0]")
 		}
@@ -1738,6 +1781,9 @@ func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 		}
 	case AlterTableChangeColumn:
 		ctx.WriteKeyWord("CHANGE COLUMN ")
+		if n.IfExists {
+			ctx.WriteKeyWord("IF EXISTS ")
+		}
 		if err := n.OldColumnName.Restore(ctx); err != nil {
 			return errors.Annotate(err, "An error occurred while restore AlterTableSpec.OldColumnName")
 		}
@@ -1788,6 +1834,9 @@ func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 		ctx.WritePlain(" /* AlterTableForce is not supported */ ")
 	case AlterTableAddPartitions:
 		ctx.WriteKeyWord("ADD PARTITION")
+		if n.IfNotExists {
+			ctx.WriteKeyWord(" IF NOT EXISTS")
+		}
 		if n.PartDefinitions != nil {
 			ctx.WritePlain(" (")
 			for i, def := range n.PartDefinitions {
@@ -1808,6 +1857,9 @@ func (n *AlterTableSpec) Restore(ctx *RestoreCtx) error {
 		ctx.WritePlainf("%d", n.Num)
 	case AlterTableDropPartition:
 		ctx.WriteKeyWord("DROP PARTITION ")
+		if n.IfExists {
+			ctx.WriteKeyWord("IF EXISTS ")
+		}
 		for i, name := range n.PartitionNames {
 			if i != 0 {
 				ctx.WritePlain(",")