feat(spanner/spansql): add support for ALTER INDEX statement (#7287)

googleapis · Jan 23, 2023 · fbe1bd4 · fbe1bd4
1 parent e528221
commit fbe1bd4
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Showing 5 changed files with 122 additions and 1 deletion.
diff --git a/spanner/spansql/parser.go b/spanner/spansql/parser.go
@@ -1053,6 +1053,9 @@ func (p *parser) parseDDLStmt() (DDLStmt, *parseError) {
 	} else if p.sniff("ALTER", "STATISTICS") {
 		as, err := p.parseAlterStatistics()
 		return as, err
+	} else if p.sniff("ALTER", "INDEX") {
+		ai, err := p.parseAlterIndex()
+		return ai, err
 	}
 
 	return nil, p.errorf("unknown DDL statement")
@@ -2321,6 +2324,52 @@ func (p *parser) parseStatisticsOptions() (StatisticsOptions, *parseError) {
 	return opts, nil
 }
 
+func (p *parser) parseAlterIndex() (*AlterIndex, *parseError) {
+	debugf("parseAlterIndex: %v", p)
+
+	if err := p.expect("ALTER"); err != nil {
+		return nil, err
+	}
+	pos := p.Pos()
+	if err := p.expect("INDEX"); err != nil {
+		return nil, err
+	}
+	iname, err := p.parseTableOrIndexOrColumnName()
+	if err != nil {
+		return nil, err
+	}
+
+	a := &AlterIndex{Name: iname, Position: pos}
+	tok := p.next()
+	if tok.err != nil {
+		return nil, tok.err
+	}
+	switch {
+	case tok.caseEqual("ADD"):
+		if err := p.expect("STORED", "COLUMN"); err != nil {
+			return nil, err
+		}
+		cname, err := p.parseTableOrIndexOrColumnName()
+		if err != nil {
+			return nil, err
+		}
+		a.Alteration = AddStoredColumn{Name: cname}
+		return a, nil
+	case tok.caseEqual("DROP"):
+		if err := p.expect("STORED", "COLUMN"); err != nil {
+			return nil, err
+		}
+		cname, err := p.parseTableOrIndexOrColumnName()
+		if err != nil {
+			return nil, err
+		}
+		a.Alteration = DropStoredColumn{Name: cname}
+		return a, nil
+	}
+
+	return nil, p.errorf("got %q, expected ADD or DROP", tok.value)
+}
+
 var baseTypes = map[string]TypeBase{
 	"BOOL":      Bool,
 	"INT64":     Int64,

diff --git a/spanner/spansql/parser_test.go b/spanner/spansql/parser_test.go
@@ -668,6 +668,9 @@ func TestParseDDL(t *testing.T) {
 		ALTER TABLE DefaultCol ALTER COLUMN Age SET DEFAULT (0);
 		ALTER TABLE DefaultCol ALTER COLUMN Age STRING(MAX) DEFAULT ("0");
 
+		ALTER INDEX MyFirstIndex ADD STORED COLUMN UpdatedAt;
+		ALTER INDEX MyFirstIndex DROP STORED COLUMN UpdatedAt;
+
 		-- Trailing comment at end of file.
 		`, &DDL{Filename: "filename", List: []DDLStmt{
 			&CreateTable{
@@ -954,6 +957,16 @@ func TestParseDDL(t *testing.T) {
 				},
 				Position: line(83),
 			},
+			&AlterIndex{
+				Name:       "MyFirstIndex",
+				Alteration: AddStoredColumn{Name: "UpdatedAt"},
+				Position:   line(85),
+			},
+			&AlterIndex{
+				Name:       "MyFirstIndex",
+				Alteration: DropStoredColumn{Name: "UpdatedAt"},
+				Position:   line(86),
+			},
 		}, Comments: []*Comment{
 			{
 				Marker: "#", Start: line(2), End: line(2),
@@ -989,7 +1002,7 @@ func TestParseDDL(t *testing.T) {
 			{Marker: "--", Isolated: true, Start: line(75), End: line(75), Text: []string{"Table has a column with a default value."}},
 
 			// Comment after everything else.
-			{Marker: "--", Isolated: true, Start: line(85), End: line(85), Text: []string{"Trailing comment at end of file."}},
+			{Marker: "--", Isolated: true, Start: line(88), End: line(88), Text: []string{"Trailing comment at end of file."}},
 		}}},
 		// No trailing comma:
 		{`ALTER TABLE T ADD COLUMN C2 INT64`, &DDL{Filename: "filename", List: []DDLStmt{

diff --git a/spanner/spansql/sql.go b/spanner/spansql/sql.go
@@ -339,6 +339,18 @@ func (sa StatisticsOptions) SQL() string {
 	return str
 }
 
+func (ai AlterIndex) SQL() string {
+	return "ALTER INDEX " + ai.Name.SQL() + " " + ai.Alteration.SQL()
+}
+
+func (asc AddStoredColumn) SQL() string {
+	return "ADD STORED COLUMN " + asc.Name.SQL()
+}
+
+func (dsc DropStoredColumn) SQL() string {
+	return "DROP STORED COLUMN " + dsc.Name.SQL()
+}
+
 func (d *Delete) SQL() string {
 	return "DELETE FROM " + d.Table.SQL() + " WHERE " + d.Where.SQL()
 }

diff --git a/spanner/spansql/sql_test.go b/spanner/spansql/sql_test.go
@@ -466,6 +466,28 @@ func TestSQL(t *testing.T) {
 			"ALTER STATISTICS auto_20191128_14_47_22UTC SET OPTIONS (allow_gc=false)",
 			reparseDDL,
 		},
+		{
+			&AlterIndex{
+				Name: "iname",
+				Alteration: AddStoredColumn{
+					Name: "cname",
+				},
+				Position: line(1),
+			},
+			"ALTER INDEX iname ADD STORED COLUMN cname",
+			reparseDDL,
+		},
+		{
+			&AlterIndex{
+				Name: "iname",
+				Alteration: DropStoredColumn{
+					Name: "cname",
+				},
+				Position: line(1),
+			},
+			"ALTER INDEX iname DROP STORED COLUMN cname",
+			reparseDDL,
+		},
 		{
 			&Insert{
 				Table:   "Singers",

diff --git a/spanner/spansql/types.go b/spanner/spansql/types.go
@@ -1146,3 +1146,28 @@ func (SetStatisticsOptions) isStatisticsAlteration() {}
 type StatisticsOptions struct {
 	AllowGC *bool
 }
+
+type AlterIndex struct {
+	Name       ID
+	Alteration IndexAlteration
+
+	Position Position // position of the "ALTER" token
+}
+
+func (as *AlterIndex) String() string { return fmt.Sprintf("%#v", as) }
+func (*AlterIndex) isDDLStmt()        {}
+func (as *AlterIndex) Pos() Position  { return as.Position }
+func (as *AlterIndex) clearOffset()   { as.Position.Offset = 0 }
+
+type IndexAlteration interface {
+	isIndexAlteration()
+	SQL() string
+}
+
+func (AddStoredColumn) isIndexAlteration()  {}
+func (DropStoredColumn) isIndexAlteration() {}
+
+type (
+	AddStoredColumn  struct{ Name ID }
+	DropStoredColumn struct{ Name ID }
+)