Refactor dialect

customize_column_test.go

@@ -26,7 +26,7 @@ func TestCustomizeColumn(t *testing.T) {
 	DB.AutoMigrate(&CustomizeColumn{})
 
 	scope := DB.NewScope(&CustomizeColumn{})
-	if !scope.Dialect().HasColumn(scope, scope.TableName(), col) {
+	if !scope.Dialect().HasColumn(scope.TableName(), col) {
 		t.Errorf("CustomizeColumn should have column %s", col)
 	}
 

ddl_errors_test.go

@@ -17,8 +17,7 @@ func TestDdlErrors(t *testing.T) {
 		}
 	}()
 
-	DB.HasTable("foobarbaz")
-	if DB.Error == nil {
+	if err := DB.Find(&User{}).Error; err == nil {
 		t.Errorf("Expected operation on closed db to produce an error, but err was nil")
 	}
 }

dialect.go

@@ -10,6 +10,9 @@ import (
 
 // Dialect interface contains behaviors that differ across SQL database
 type Dialect interface {
+	// SetDB set db for dialect
+	SetDB(db *sql.DB)
+
 	// BindVar return the placeholder for actual values in SQL statements, in many dbs it is "?", Postgres using $1
 	BindVar(i int) string
 	// Quote quotes field name to avoid SQL parsing exceptions by using a reserved word as a field name
@@ -18,13 +21,13 @@ type Dialect interface {
 	DataTypeOf(field *StructField) string
 
 	// HasIndex check has index or not
-	HasIndex(scope *Scope, tableName string, indexName string) bool
+	HasIndex(tableName string, indexName string) bool
 	// RemoveIndex remove index
-	RemoveIndex(scope *Scope, indexName string)
+	RemoveIndex(tableName string, indexName string) error
 	// HasTable check has table or not
-	HasTable(scope *Scope, tableName string) bool
+	HasTable(tableName string) bool
 	// HasColumn check has column or not
-	HasColumn(scope *Scope, tableName string, columnName string) bool
+	HasColumn(tableName string, columnName string) bool
 
 	// LimitAndOffsetSQL return generate SQL with limit and offset, as mssql has special case
 	LimitAndOffsetSQL(limit, offset int) string
@@ -36,12 +39,17 @@ type Dialect interface {
 
 var dialectsMap = map[string]Dialect{}
 
-func newDialect(name string) Dialect {
-	if dialect, ok := dialectsMap[name]; ok {
+func newDialect(name string, db *sql.DB) Dialect {
+	if value, ok := dialectsMap[name]; ok {
+		dialect := reflect.New(reflect.TypeOf(value).Elem()).Interface().(Dialect)
+		dialect.SetDB(db)
 		return dialect
 	}
+
 	fmt.Printf("`%v` is not officially supported, running under compatibility mode.\n", name)
-	return &commonDialect{}
+	commontDialect := &commonDialect{}
+	commontDialect.SetDB(db)
+	return commontDialect
 }
 
 // RegisterDialect register new dialect

dialect_common.go

@@ -1,18 +1,25 @@
 package gorm
 
 import (
+	"database/sql"
 	"fmt"
 	"reflect"
 	"strings"
 	"time"
 )
 
-type commonDialect struct{}
+type commonDialect struct {
+	db *sql.DB
+}
 
 func init() {
 	RegisterDialect("common", &commonDialect{})
 }
 
+func (s *commonDialect) SetDB(db *sql.DB) {
+	s.db = db
+}
+
 func (commonDialect) BindVar(i int) string {
 	return "$$" // ?
 }
@@ -73,51 +80,31 @@ func (commonDialect) DataTypeOf(field *StructField) string {
 	return fmt.Sprintf("%v %v", sqlType, additionalType)
 }
 
-func (c commonDialect) HasIndex(scope *Scope, tableName string, indexName string) bool {
-	var (
-		count        int
-		databaseName = c.currentDatabase(scope)
-	)
-	c.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.STATISTICS WHERE table_schema = ? AND table_name = ? AND index_name = ?", databaseName, tableName, indexName)
+func (s commonDialect) HasIndex(tableName string, indexName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.STATISTICS WHERE table_schema = ? AND table_name = ? AND index_name = ?", s.currentDatabase(), tableName, indexName).Scan(&count)
 	return count > 0
 }
 
-func (commonDialect) RemoveIndex(scope *Scope, indexName string) {
-	scope.Err(scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, scope.QuotedTableName())).Error)
+func (s commonDialect) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v", indexName))
+	return err
 }
 
-func (c commonDialect) HasTable(scope *Scope, tableName string) bool {
-	var (
-		count        int
-		databaseName = c.currentDatabase(scope)
-	)
-	c.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = ? AND table_name = ?", databaseName, tableName)
+func (s commonDialect) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.TABLES WHERE table_schema = ? AND table_name = ?", s.currentDatabase(), tableName).Scan(&count)
 	return count > 0
 }
 
-func (c commonDialect) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var (
-		count        int
-		databaseName = c.currentDatabase(scope)
-	)
-	c.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE table_schema = ? AND table_name = ? AND column_name = ?", databaseName, tableName, columnName)
+func (s commonDialect) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE table_schema = ? AND table_name = ? AND column_name = ?", s.currentDatabase(), tableName, columnName).Scan(&count)
 	return count > 0
 }
 
-// RawScanInt scans the first column of the first row into the `scan' int pointer.
-// This function captures raw query errors and propagates them to the original scope.
-func (commonDialect) RawScanInt(scope *Scope, scanPtr *int, query string, args ...interface{}) {
-	scope.Err(scope.NewDB().Raw(query, args...).Row().Scan(scanPtr))
-}
-
-// RawScanString scans the first column of the first row into the `scan' string pointer.
-// This function captures raw query errors and propagates them to the original scope.
-func (commonDialect) RawScanString(scope *Scope, scanPtr *string, query string, args ...interface{}) {
-	scope.Err(scope.NewDB().Raw(query, args...).Row().Scan(scanPtr))
-}
-
-func (commonDialect) currentDatabase(scope *Scope) (name string) {
-	scope.Err(scope.NewDB().Raw("SELECT DATABASE()").Row().Scan(&name))
+func (s commonDialect) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT DATABASE()").Scan(&name)
 	return
 }
 

dialect_mssql.go

@@ -67,32 +67,31 @@ func (mssql) DataTypeOf(field *StructField) string {
 	return fmt.Sprintf("%v %v", sqlType, additionalType)
 }
 
-func (s mssql) HasIndex(scope *Scope, tableName string, indexName string) bool {
+func (s mssql) HasIndex(tableName string, indexName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM sys.indexes WHERE name=? AND object_id=OBJECT_ID(?)", indexName, tableName)
+	s.db.QueryRow("SELECT count(*) FROM sys.indexes WHERE name=? AND object_id=OBJECT_ID(?)", indexName, tableName).Scan(&count)
 	return count > 0
 }
 
-func (s mssql) HasTable(scope *Scope, tableName string) bool {
-	var (
-		count        int
-		databaseName = s.currentDatabase(scope)
-	)
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = ? AND table_catalog = ?", tableName, databaseName)
+func (s mssql) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, s.Quote(tableName)))
+	return err
+}
+
+func (s mssql) HasTable(tableName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = ? AND table_catalog = ?", tableName, s.currentDatabase()).Scan(&count)
 	return count > 0
 }
 
-func (s mssql) HasColumn(scope *Scope, tableName string, columnName string) bool {
-	var (
-		count        int
-		databaseName = s.currentDatabase(scope)
-	)
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM information_schema.columns WHERE table_catalog = ? AND table_name = ? AND column_name = ?", databaseName, tableName, columnName)
+func (s mssql) HasColumn(tableName string, columnName string) bool {
+	var count int
+	s.db.QueryRow("SELECT count(*) FROM information_schema.columns WHERE table_catalog = ? AND table_name = ? AND column_name = ?", s.currentDatabase(), tableName, columnName).Scan(&count)
 	return count > 0
 }
 
-func (s mssql) currentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT DB_NAME() AS [Current Database]")
+func (s mssql) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT DB_NAME() AS [Current Database]").Scan(&name)
 	return
 }
 

dialect_mysql.go

@@ -88,8 +88,13 @@ func (mysql) DataTypeOf(field *StructField) string {
 	return fmt.Sprintf("%v %v", sqlType, additionalType)
 }
 
-func (s mysql) currentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT DATABASE()")
+func (s mysql) RemoveIndex(tableName string, indexName string) error {
+	_, err := s.db.Exec(fmt.Sprintf("DROP INDEX %v ON %v", indexName, s.Quote(tableName)))
+	return err
+}
+
+func (s mysql) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT DATABASE()").Scan(&name)
 	return
 }
 

dialect_postgres.go

@@ -77,30 +77,26 @@ func (postgres) DataTypeOf(field *StructField) string {
 	return fmt.Sprintf("%v %v", sqlType, additionalType)
 }
 
-func (s postgres) HasIndex(scope *Scope, tableName string, indexName string) bool {
+func (s postgres) HasIndex(tableName string, indexName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM pg_indexes WHERE tablename = ? AND indexname = ?", tableName, indexName)
+	s.db.QueryRow("SELECT count(*) FROM pg_indexes WHERE tablename = $1 AND indexname = $2", tableName, indexName).Scan(&count)
 	return count > 0
 }
 
-func (postgres) RemoveIndex(scope *Scope, indexName string) {
-	scope.Err(scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v", indexName)).Error)
-}
-
-func (s postgres) HasTable(scope *Scope, tableName string) bool {
+func (s postgres) HasTable(tableName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = ? AND table_type = 'BASE TABLE'", tableName)
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.tables WHERE table_name = $1 AND table_type = 'BASE TABLE'", tableName).Scan(&count)
 	return count > 0
 }
 
-func (s postgres) HasColumn(scope *Scope, tableName string, columnName string) bool {
+func (s postgres) HasColumn(tableName string, columnName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_name = ? AND column_name = ?", tableName, columnName)
+	s.db.QueryRow("SELECT count(*) FROM INFORMATION_SCHEMA.columns WHERE table_name = $1 AND column_name = $2", tableName, columnName).Scan(&count)
 	return count > 0
 }
 
-func (s postgres) currentDatabase(scope *Scope) (name string) {
-	s.RawScanString(scope, &name, "SELECT CURRENT_DATABASE()")
+func (s postgres) currentDatabase() (name string) {
+	s.db.QueryRow("SELECT CURRENT_DATABASE()").Scan(&name)
 	return
 }
 

dialect_sqlite3.go

@@ -65,29 +65,25 @@ func (sqlite3) DataTypeOf(field *StructField) string {
 	return fmt.Sprintf("%v %v", sqlType, additionalType)
 }
 
-func (s sqlite3) HasIndex(scope *Scope, tableName string, indexName string) bool {
+func (s sqlite3) HasIndex(tableName string, indexName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND sql LIKE '%%INDEX %v ON%%'", indexName), tableName)
+	s.db.QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND sql LIKE '%%INDEX %v ON%%'", indexName), tableName).Scan(&count)
 	return count > 0
 }
 
-func (sqlite3) RemoveIndex(scope *Scope, indexName string) {
-	scope.Err(scope.NewDB().Exec(fmt.Sprintf("DROP INDEX %v", indexName)).Error)
-}
-
-func (s sqlite3) HasTable(scope *Scope, tableName string) bool {
+func (s sqlite3) HasTable(tableName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, "SELECT count(*) FROM sqlite_master WHERE type='table' AND name=?", tableName)
+	s.db.QueryRow("SELECT count(*) FROM sqlite_master WHERE type='table' AND name=?", tableName).Scan(&count)
 	return count > 0
 }
 
-func (s sqlite3) HasColumn(scope *Scope, tableName string, columnName string) bool {
+func (s sqlite3) HasColumn(tableName string, columnName string) bool {
 	var count int
-	s.RawScanInt(scope, &count, fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND (sql LIKE '%%(\"%v\" %%' OR sql LIKE '%%,\"%v\" %%' OR sql LIKE '%%, \"%v\" %%' OR sql LIKE '%%( %v %%' OR sql LIKE '%%, %v %%' OR sql LIKE '%%,%v %%');\n", columnName, columnName, columnName, columnName, columnName, columnName), tableName)
+	s.db.QueryRow(fmt.Sprintf("SELECT count(*) FROM sqlite_master WHERE tbl_name = ? AND (sql LIKE '%%(\"%v\" %%' OR sql LIKE '%%,\"%v\" %%' OR sql LIKE '%%, \"%v\" %%' OR sql LIKE '%%( %v %%' OR sql LIKE '%%, %v %%' OR sql LIKE '%%,%v %%');\n", columnName, columnName, columnName, columnName, columnName, columnName), tableName).Scan(&count)
 	return count > 0
 }
 
-func (sqlite3) currentDatabase(scope *Scope) (name string) {
+func (s sqlite3) currentDatabase() (name string) {
 	var (
 		ifaces   = make([]interface{}, 3)
 		pointers = make([]*string, 3)
@@ -96,7 +92,7 @@ func (sqlite3) currentDatabase(scope *Scope) (name string) {
 	for i = 0; i < 3; i++ {
 		ifaces[i] = &pointers[i]
 	}
-	if err := scope.NewDB().Raw("PRAGMA database_list").Row().Scan(ifaces...); scope.Err(err) != nil {
+	if err := s.db.QueryRow("PRAGMA database_list").Scan(ifaces...); err != nil {
 		return
 	}
 	if pointers[1] != nil {

main.go

@@ -62,7 +62,7 @@ func Open(dialect string, args ...interface{}) (*DB, error) {
 		}
 
 		db = DB{
-			dialect:   newDialect(dialect),
+			dialect:   newDialect(dialect, dbSql.(*sql.DB)),
 			logger:    defaultLogger,
 			callbacks: defaultCallback,
 			source:    source,
@@ -430,7 +430,7 @@ func (s *DB) HasTable(value interface{}) bool {
 		tableName = scope.TableName()
 	}
 
-	has := scope.Dialect().HasTable(scope, tableName)
+	has := scope.Dialect().HasTable(tableName)
 	s.AddError(scope.db.Error)
 	return has
 }
@@ -531,7 +531,7 @@ func (s *DB) SetJoinTableHandler(source interface{}, column string, handler Join
 				destination := (&Scope{Value: reflect.New(field.Struct.Type).Interface()}).GetModelStruct().ModelType
 				handler.Setup(field.Relationship, many2many, source, destination)
 				field.Relationship.JoinTableHandler = handler
-				if table := handler.Table(s); scope.Dialect().HasTable(scope, table) {
+				if table := handler.Table(s); scope.Dialect().HasTable(table) {
 					s.Table(table).AutoMigrate(handler)
 				}
 			}