parser: add support for ALTER DATABASE syntax

ast/ddl.go

@@ -118,6 +118,42 @@ func (n *CreateDatabaseStmt) Accept(v Visitor) (Node, bool) {
 	return v.Leave(n)
 }
 
+// AlterDatabaseStmt is a statement to change the structure of a database.
+// See https://dev.mysql.com/doc/refman/5.7/en/alter-database.html
+type AlterDatabaseStmt struct {
+	ddlNode
+
+	Name    string
+	Options []*DatabaseOption
+}
+
+// Restore implements Node interface.
+func (n *AlterDatabaseStmt) Restore(ctx *RestoreCtx) error {
+	ctx.WriteKeyWord("ALTER DATABASE")
+	if n.Name != "" {
+		ctx.WritePlain(" ")
+		ctx.WriteName(n.Name)
+	}
+	for _, option := range n.Options {
+		ctx.WritePlain(" ")
+		err := option.Restore(ctx)
+		if err != nil {
+			return errors.Trace(err)
+		}
+	}
+	return nil
+}
+
+// Accept implements Node Accept interface.
+func (n *AlterDatabaseStmt) Accept(v Visitor) (Node, bool) {
+	newNode, skipChildren := v.Enter(n)
+	if skipChildren {
+		return v.Leave(newNode)
+	}
+	n = newNode.(*AlterDatabaseStmt)
+	return v.Leave(n)
+}
+
 // DropDatabaseStmt is a statement to drop a database and all tables in the database.
 // See https://dev.mysql.com/doc/refman/5.7/en/drop-database.html
 type DropDatabaseStmt struct {

ast/ddl_test.go

@@ -35,6 +35,7 @@ func (ts *testDDLSuite) TestDDLVisitorCover(c *C) {
 		expectedLeaveCnt int
 	}{
 		{&CreateDatabaseStmt{}, 0, 0},
+		{&AlterDatabaseStmt{}, 0, 0},
 		{&DropDatabaseStmt{}, 0, 0},
 		{&DropIndexStmt{Table: &TableName{}}, 0, 0},
 		{&DropTableStmt{Tables: []*TableName{{}, {}}}, 0, 0},