add upstream 2f8eadc19c53fece3b19247d937cd75ebc400e5f support for Tru…

…ncateTables on all 3 dialects

dbmap.go

@@ -370,6 +370,19 @@ func (m *DbMap) TableForType(t reflect.Type) *TableMap {
 	return nil
 }
 
+// Truncate all tables in the DbMap
+func (m *DbMap) TruncateTables() error {
+	var err error
+	for i := range m.tables {
+		table := m.tables[i]
+		_, e := m.Exec(fmt.Sprintf("%s %s;", m.Dialect.TruncateClause(), m.Dialect.QuoteField(table.TableName)))
+		if e != nil {
+			err = e
+		}
+	}
+	return err
+}
+
 func (m *DbMap) queryRow(query string, args ...interface{}) *sql.Row {
 	m.trace(query, args)
 	return m.Db.QueryRow(query, args...)

dialect.go

@@ -42,6 +42,9 @@ type Dialect interface {
 	// SQL parsing exceptions by using a reserved word as a field name.
 	QuoteField(field string) string
 
+	// string used to truncate tables
+	TruncateClause() string
+
 	// Get the driver name from a dialect
 	DriverName() string
 }
@@ -126,6 +129,13 @@ func (d SqliteDialect) QuoteField(f string) string {
 	return `"` + f + `"`
 }
 
+// With sqlite, there technically isn't a TRUNCATE statement,
+// but a DELETE FROM uses a truncate optimization:
+// http://www.sqlite.org/lang_delete.html
+func (d SqliteDialect) TruncateClause() string {
+	return "delete from"
+}
+
 ///////////////////////////////////////////////////////
 // PostgreSQL //
 ////////////////
@@ -222,6 +232,10 @@ func (d PostgresDialect) QuoteField(f string) string {
 	return `"` + strings.ToLower(f) + `"`
 }
 
+func (d PostgresDialect) TruncateClause() string {
+	return "truncate"
+}
+
 ///////////////////////////////////////////////////////
 // MySQL //
 ///////////
@@ -319,3 +333,7 @@ func ReBind(query string, dialect Dialect) string {
 	}
 	return query
 }
+
+func (m MySQLDialect) TruncateClause() string {
+	return "truncate"
+}

modl_test.go

@@ -711,6 +711,38 @@ func initDbMap() *DbMap {
 	return dbmap
 }
 
+func TestTruncateTables(t *testing.T) {
+	dbmap := initDbMap()
+	defer dbmap.DropTables()
+	err := dbmap.CreateTablesIfNotExists()
+	if err != nil {
+		t.Error(err)
+	}
+
+	// Insert some data
+	p1 := &Person{0, 0, 0, "Bob", "Smith", 0}
+	dbmap.Insert(p1)
+	inv := &Invoice{0, 0, 1, "my invoice", 0, true}
+	dbmap.Insert(inv)
+
+	err = dbmap.TruncateTables()
+	if err != nil {
+		t.Error(err)
+	}
+
+	// Make sure all rows are deleted
+	people := []Person{}
+	invoices := []Invoice{}
+	dbmap.Select(&people, "SELECT * FROM person_test")
+	if len(people) != 0 {
+		t.Errorf("Expected 0 person rows, got %d", len(people))
+	}
+	dbmap.Select(&invoices, "SELECT * FROM invoice_test")
+	if len(invoices) != 0 {
+		t.Errorf("Expected 0 invoice rows, got %d", len(invoices))
+	}
+}
+
 func TestQuoteTableNames(t *testing.T) {
 	dbmap := initDbMap()
 	defer dbmap.DropTables()