sql/ast: Implement ALTER TABLE RENAME column (#399)

Author: kyleconroy

internal/postgresql/catalog_test.go

@@ -153,26 +153,26 @@ func TestUpdate(t *testing.T) {
 				},
 			},
 		},
-		/*
-			{
-				`
-				CREATE TABLE foo (bar text);
-				ALTER TABLE foo RENAME bar TO baz;
-				`,
-				pg.Catalog{
-					Schemas: map[string]pg.Schema{
-						"public": {
-							Tables: map[string]pg.Table{
-								"foo": pg.Table{
-									Name:    "foo",
-									Columns: []pg.Column{{Name: "baz", DataType: "text", Table: pg.FQN{Schema: "public", Rel: "foo"}}},
-								},
+		{
+			`
+			CREATE TABLE foo (bar text);
+			ALTER TABLE foo RENAME bar TO baz;
+			`,
+			&catalog.Schema{
+				Name: "public",
+				Tables: []*catalog.Table{
+					{
+						Rel: &ast.TableName{Name: "foo"},
+						Columns: []*catalog.Column{
+							{
+								Name: "baz",
+								Type: ast.TypeName{Name: "text"},
 							},
 						},
 					},
 				},
 			},
-		*/
+		},
 		{
 			`
 			CREATE TABLE foo (bar text);

internal/postgresql/parse.go

@@ -368,6 +368,17 @@ func translate(node nodes.Node) (ast.Node, error) {
 	case nodes.RenameStmt:
 		switch n.RenameType {
 
+		case nodes.OBJECT_COLUMN:
+			tbl, err := parseTableName(*n.Relation)
+			if err != nil {
+				return nil, err
+			}
+			return &ast.RenameColumnStmt{
+				Table:   tbl,
+				Col:     &ast.ColumnRef{Name: *n.Subname},
+				NewName: n.Newname,
+			}, nil
+
 		case nodes.OBJECT_TABLE:
 			tbl, err := parseTableName(*n.Relation)
 			if err != nil {

internal/sql/ast/ast.go

@@ -210,6 +210,16 @@ func (n *CommentOnColumnStmt) Pos() int {
 	return 0
 }
 
+type RenameColumnStmt struct {
+	Table   *TableName
+	Col     *ColumnRef
+	NewName *string
+}
+
+func (n *RenameColumnStmt) Pos() int {
+	return 0
+}
+
 type RenameTableStmt struct {
 	Table   *TableName
 	NewName *string

internal/sql/catalog/catalog.go

@@ -165,6 +165,8 @@ func (c *Catalog) Build(stmts []ast.Statement) error {
 			err = c.dropTable(n)
 		case *ast.DropTypeStmt:
 			err = c.dropType(n)
+		case *ast.RenameColumnStmt:
+			err = c.renameColumn(n)
 		case *ast.RenameTableStmt:
 			err = c.renameTable(n)
 		}

internal/sql/catalog/table.go

@@ -146,6 +146,27 @@ func (c *Catalog) dropTable(stmt *ast.DropTableStmt) error {
 	return nil
 }
 
+func (c *Catalog) renameColumn(stmt *ast.RenameColumnStmt) error {
+	_, tbl, err := c.getTable(stmt.Table)
+	if err != nil {
+		return err
+	}
+	idx := -1
+	for i := range tbl.Columns {
+		if tbl.Columns[i].Name == stmt.Col.Name {
+			idx = i
+		}
+		if tbl.Columns[i].Name == *stmt.NewName {
+			return sqlerr.ColumnExists(tbl.Rel.Name, *stmt.NewName)
+		}
+	}
+	if idx == -1 {
+		return sqlerr.ColumnNotFound(tbl.Rel.Name, stmt.Col.Name)
+	}
+	tbl.Columns[idx].Name = *stmt.NewName
+	return nil
+}
+
 func (c *Catalog) renameTable(stmt *ast.RenameTableStmt) error {
 	_, tbl, err := c.getTable(stmt.Table)
 	if err != nil {