Fix remove index for sqlite and postgres

common_dialect.go

@@ -98,3 +98,7 @@ func (s *commonDialect) HasColumn(scope *Scope, tableName string, columnName str
 	newScope.DB().QueryRow(newScope.Sql, newScope.SqlVars...).Scan(&count)
 	return count > 0
 }
+
+func (s *commonDialect) RemoveIndex(scope *Scope, indexName string) {
+	scope.Raw(fmt.Sprintf("DROP INDEX %v ON %v", indexName, scope.QuotedTableName())).Exec()
+}

dialect.go

@@ -17,6 +17,7 @@ type Dialect interface {
 	Quote(key string) string
 	HasTable(scope *Scope, tableName string) bool
 	HasColumn(scope *Scope, tableName string, columnName string) bool
+	RemoveIndex(scope *Scope, indexName string)
 }
 
 func NewDialect(driver string) Dialect {

migration_test.go

@@ -68,6 +68,7 @@ func TestIndexes(t *testing.T) {
 	if err := db.Model(&Email{}).AddIndex("idx_email_email_and_user_id", "user_id", "email").Error; err != nil {
 		t.Errorf("Got error when tried to create index: %+v", err)
 	}
+
 	if err := db.Model(&Email{}).RemoveIndex("idx_email_email_and_user_id").Error; err != nil {
 		t.Errorf("Got error when tried to remove index: %+v", err)
 	}
@@ -76,8 +77,15 @@ func TestIndexes(t *testing.T) {
 		t.Errorf("Got error when tried to create index: %+v", err)
 	}
 
-	fmt.Println(db.Save(&User{Name: "unique_indexes", Emails: []Email{{Email: "user1@example.comiii"}, {Email: "user1@example.com"}, {Email: "user1@example.com"}}}).Error)
-	if db.Debug().Save(&User{Name: "unique_indexes", Emails: []Email{{Email: "user1@example.comiii"}, {Email: "user1@example.com"}, {Email: "user1@example.com"}}}).Error == nil {
+	if db.Save(&User{Name: "unique_indexes", Emails: []Email{{Email: "user1@example.comiii"}, {Email: "user1@example.com"}, {Email: "user1@example.com"}}}).Error == nil {
 		t.Errorf("Should get to create duplicate record when having unique index")
 	}
+
+	if err := db.Model(&Email{}).RemoveIndex("idx_email_email_and_user_id").Error; err != nil {
+		t.Errorf("Got error when tried to remove index: %+v", err)
+	}
+
+	if db.Save(&User{Name: "unique_indexes", Emails: []Email{{Email: "user1@example.com"}, {Email: "user1@example.com"}}}).Error != nil {
+		t.Errorf("Should be able to create duplicated emails after remove unique index")
+	}
 }

mysql.go

@@ -99,3 +99,7 @@ func (s *mysql) HasColumn(scope *Scope, tableName string, columnName string) boo
 	newScope.DB().QueryRow(newScope.Sql, newScope.SqlVars...).Scan(&count)
 	return count > 0
 }
+
+func (s *mysql) RemoveIndex(scope *Scope, indexName string) {
+	scope.Raw(fmt.Sprintf("DROP INDEX %v ON %v", indexName, scope.QuotedTableName())).Exec()
+}

postgres.go

@@ -89,6 +89,10 @@ func (s *postgres) HasColumn(scope *Scope, tableName string, columnName string)
 	return count > 0
 }
 
+func (s *postgres) RemoveIndex(scope *Scope, indexName string) {
+	scope.Raw(fmt.Sprintf("DROP INDEX %v", indexName)).Exec()
+}
+
 var hstoreType = reflect.TypeOf(Hstore{})
 
 type Hstore map[string]*string

scope_private.go

@@ -445,7 +445,7 @@ func (scope *Scope) addIndex(unique bool, indexName string, column ...string) {
 }
 
 func (scope *Scope) removeIndex(indexName string) {
-	scope.Raw(fmt.Sprintf("DROP INDEX %v ON %v", indexName, scope.QuotedTableName())).Exec()
+	scope.Dialect().RemoveIndex(scope, indexName)
 }
 
 func (scope *Scope) autoMigrate() *Scope {

sqlite3.go

@@ -71,3 +71,7 @@ func (s *sqlite3) HasColumn(scope *Scope, tableName string, columnName string) b
 	scope.DB().QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = '%v' AND (sql LIKE '%%(\"%v\" %%' OR sql LIKE '%%,\"%v\" %%' OR sql LIKE '%%( %v %%' OR sql LIKE '%%, %v %%');\n", tableName, columnName, columnName, columnName, columnName)).Scan(&count)
 	return count > 0
 }
+
+func (s *sqlite3) RemoveIndex(scope *Scope, indexName string) {
+	scope.Raw(fmt.Sprintf("DROP INDEX %v", indexName)).Exec()
+}

structs_test.go

@@ -101,7 +101,7 @@ type CreditCard struct {
 type Email struct {
 	Id        int16
 	UserId    int
-	Email     string `sql:"type:varchar(100); unique"`
+	Email     string `sql:"type:varchar(100);"`
 	CreatedAt time.Time
 	UpdatedAt time.Time
 }