add comments for orm packages, part 2

orm/db_mysql.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 )
 
+// mysql operators.
 var mysqlOperators = map[string]string{
 	"exact":     "= ?",
 	"iexact":    "LIKE ?",
@@ -21,6 +22,7 @@ var mysqlOperators = map[string]string{
 	"iendswith":   "LIKE ?",
 }
 
+// mysql column field types.
 var mysqlTypes = map[string]string{
 	"auto":            "AUTO_INCREMENT NOT NULL PRIMARY KEY",
 	"pk":              "NOT NULL PRIMARY KEY",
@@ -41,29 +43,35 @@ var mysqlTypes = map[string]string{
 	"float64-decimal": "numeric(%d, %d)",
 }
 
+// mysql dbBaser implementation.
 type dbBaseMysql struct {
 	dbBase
 }
 
 var _ dbBaser = new(dbBaseMysql)
 
+// get mysql operator.
 func (d *dbBaseMysql) OperatorSql(operator string) string {
 	return mysqlOperators[operator]
 }
 
+// get mysql table field types.
 func (d *dbBaseMysql) DbTypes() map[string]string {
 	return mysqlTypes
 }
 
+// show table sql for mysql.
 func (d *dbBaseMysql) ShowTablesQuery() string {
 	return "SELECT table_name FROM information_schema.tables WHERE table_type = 'BASE TABLE' AND table_schema = DATABASE()"
 }
 
+// show columns sql of table for mysql.
 func (d *dbBaseMysql) ShowColumnsQuery(table string) string {
 	return fmt.Sprintf("SELECT COLUMN_NAME, COLUMN_TYPE, IS_NULLABLE FROM information_schema.columns "+
 		"WHERE table_schema = DATABASE() AND table_name = '%s'", table)
 }
 
+// execute sql to check index exist.
 func (d *dbBaseMysql) IndexExists(db dbQuerier, table string, name string) bool {
 	row := db.QueryRow("SELECT count(*) FROM information_schema.statistics "+
 		"WHERE table_schema = DATABASE() AND table_name = ? AND index_name = ?", table, name)
@@ -72,6 +80,7 @@ func (d *dbBaseMysql) IndexExists(db dbQuerier, table string, name string) bool
 	return cnt > 0
 }
 
+// create new mysql dbBaser.
 func newdbBaseMysql() dbBaser {
 	b := new(dbBaseMysql)
 	b.ins = b