Add method to list FKs.

meta.go

@@ -40,12 +40,12 @@ func (c *Conn) Tables() ([]string, os.Error) {
 }
 
 type Column struct {
-	cid int
-	name string
-	dataType string
-	notNull bool
-	dfltValue string // FIXME type ?
-	pk bool
+	Cid       int
+	Name      string
+	DataType  string
+	NotNull   bool
+	DfltValue string // FIXME type ?
+	Pk        bool
 }
 
 func (c *Conn) Columns(table string) ([]Column, os.Error) {
@@ -53,19 +53,51 @@ func (c *Conn) Columns(table string) ([]Column, os.Error) {
 	if err != nil {
 		return nil, err
 	}
-	if err != nil {
-		return nil, err
-	}
 	var columns []Column = make([]Column, 0, 20)
 	var ok bool
 	for ok, err = s.Next(); ok; ok, err = s.Next() {
 		c := Column{}
-		s.Scan(&c.cid, &c.name, &c.dataType, &c.notNull, &c.dfltValue, &c.pk)
+		err = s.Scan(&c.Cid, &c.Name, &c.DataType, &c.NotNull, &c.DfltValue, &c.Pk)
+		if err != nil {
+			return nil, err
+		}
 		columns = append(columns, c)
 	}
+	if err != nil {
+		return nil, err
+	}
 	return columns, nil
 }
 
+type ForeignKey struct {
+	Id    int
+	Seq   int
+	Table string
+	From  string
+	To    string
+}
+
+func (c *Conn) ForeignKeys(table string) ([]ForeignKey, os.Error) {
+	s, err := c.Prepare(Mprintf("pragma foreign_key_list(%Q)", table))
+	if err != nil {
+		return nil, err
+	}
+	var fks []ForeignKey = make([]ForeignKey, 0, 20)
+	var ok bool
+	for ok, err = s.Next(); ok; ok, err = s.Next() {
+		fk := ForeignKey{}
+		err = s.NamedScan("id", &fk.Id, "seq", &fk.Seq, "table", &fk.Table, "from", &fk.From, "to", &fk.To)
+		if err != nil {
+			return nil, err
+		}
+		fks = append(fks, fk)
+	}
+	if err != nil {
+		return nil, err
+	}
+	return fks, nil
+}
+
 func Mprintf(format string, arg string) string {
 	cf := C.CString(format)
 	defer C.free(unsafe.Pointer(cf))

sqlite_test.go

@@ -198,6 +198,7 @@ func TestInsertWithStatement(t *testing.T) {
 func TestTables(t *testing.T) {
 	db := open(t)
 	defer db.Close()
+
 	tables, err := db.Tables()
 	if err != nil {
 		t.Fatalf("error looking for tables: %s", err)
@@ -216,16 +217,46 @@ func TestTables(t *testing.T) {
 	if tables[0] != "test" {
 		t.Errorf("Wrong table name: 'test' <> %s\n", tables[0])
 	}
+}
+
+func TestColumns(t *testing.T) {
+	db := open(t)
+	defer db.Close()
+	createTable(db, t)
+
 	columns, err := db.Columns("test")
 	if err != nil {
-		t.Fatalf("error looking for columns: %s", err)
+		t.Fatalf("error listing columns: %s", err)
 	}
 	if len(columns) != 4 {
-		t.Errorf("Expected 4 columns <> %d", len(columns))
+		t.Fatalf("Expected 4 columns <> %d", len(columns))
 	}
 	column := columns[2]
-	if column.name != "int_num" {
-		t.Errorf("Wrong column name: 'int_num' <> %s", column.name)
+	if column.Name != "int_num" {
+		t.Errorf("Wrong column name: 'int_num' <> %s", column.Name)
+	}
+}
+
+func TestForeignKeys(t *testing.T) {
+	db := open(t)
+	defer db.Close()
+
+	err := db.Exec("CREATE TABLE parent (id INTEGER PRIMARY KEY);" +
+		"CREATE TABLE child (id INTEGER PRIMARY KEY, parentId INTEGER, " +
+		"FOREIGN KEY (parentId) REFERENCES parent(id));")
+	if err != nil {
+		t.Fatalf("error creating tables: %s", err)
+	}
+	fks, err := db.ForeignKeys("child")
+	if err != nil {
+		t.Fatalf("error listing FKs: %s", err)
+	}
+	if len(fks) != 1 {
+		t.Fatalf("Expected 1 FK <> %d", len(fks))
+	}
+	fk := fks[0]
+	if fk.From != "parentId" || fk.Table != "parent" || fk.To != "id" {
+		t.Errorf("Unexpected FK data: %#v", fk)
 	}
 }