From 044198f373ea96ccbbfc439a7e8041115b706041 Mon Sep 17 00:00:00 2001
From: Lunny Xiao <xiaolunwen@gmail.com>
Date: Fri, 13 Mar 2015 15:20:24 +0800
Subject: [PATCH] oracle drop table fixed

---
 oracle_dialect.go |  8 ++++++++
 session.go        | 50 ++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 47 insertions(+), 11 deletions(-)

diff --git a/oracle_dialect.go b/oracle_dialect.go
index 5caa0b27..be71c288 100644
--- a/oracle_dialect.go
+++ b/oracle_dialect.go
@@ -565,10 +565,18 @@ func (db *oracle) SupportCharset() bool {
 	return false
 }
 
+func (db *oracle) SupportDropIfExists() bool {
+	return false
+}
+
 func (db *oracle) IndexOnTable() bool {
 	return false
 }
 
+func (db *oracle) DropTableSql(tableName string) string {
+	return fmt.Sprintf("DROP TABLE `%s`", tableName)
+}
+
 func (b *oracle) CreateTableSql(table *core.Table, tableName, storeEngine, charset string) string {
 	var sql string
 	sql = "CREATE TABLE "
diff --git a/session.go b/session.go
index f5dc9b89..04cd96bd 100644
--- a/session.go
+++ b/session.go
@@ -563,7 +563,7 @@ func (session *Session) DropIndexes(bean interface{}) error {
 }
 
 // DropTable drop a table and all indexes of the table
-func (session *Session) DropTable(bean interface{}) error {
+/*func (session *Session) DropTable(bean interface{}) error {
 	defer session.resetStatement()
 	if session.IsAutoClose {
 		defer session.Close()
@@ -583,6 +583,30 @@ func (session *Session) DropTable(bean interface{}) error {
 	sqlStr := session.Engine.Dialect().DropTableSql(session.Statement.TableName())
 	_, err := session.exec(sqlStr)
 	return err
+}*/
+
+func (session *Session) DropTable(beanOrTableName interface{}) error {
+	tableName, err := session.Engine.tableName(beanOrTableName)
+	if err != nil {
+		return err
+	}
+
+	var needDrop = true
+	if !session.Engine.dialect.SupportDropIfExists() {
+		sqlStr, args := session.Engine.dialect.TableCheckSql(tableName)
+		results, err := session.query(sqlStr, args...)
+		if err != nil {
+			return err
+		}
+		needDrop = len(results) > 0
+	}
+
+	if needDrop {
+		sqlStr := session.Engine.Dialect().DropTableSql(tableName)
+		_, err = session.exec(sqlStr)
+		return err
+	}
+	return nil
 }
 
 func (statement *Statement) JoinColumns(cols []*core.Column) string {
@@ -1367,16 +1391,21 @@ func (session *Session) isColumnExist(tableName string, col *core.Column) (bool,
 	//return len(results) > 0, err
 }*/
 
-func (session *Session) IsTableExist(beanOrTableName interface{}) (bool, error) {
+func (engine *Engine) tableName(beanOrTableName interface{}) (string, error) {
 	v := rValue(beanOrTableName)
-	var tableName string
 	if v.Type().Kind() == reflect.String {
-		tableName = beanOrTableName.(string)
+		return beanOrTableName.(string), nil
 	} else if v.Type().Kind() == reflect.Struct {
-		table := session.Engine.autoMapType(v)
-		tableName = table.Name
-	} else {
-		return false, errors.New("bean should be a struct or struct's point")
+		table := engine.autoMapType(v)
+		return table.Name, nil
+	}
+	return "", errors.New("bean should be a struct or struct's point")
+}
+
+func (session *Session) IsTableExist(beanOrTableName interface{}) (bool, error) {
+	tableName, err := session.Engine.tableName(beanOrTableName)
+	if err != nil {
+		return false, err
 	}
 
 	return session.isTableExist(tableName)
@@ -1507,9 +1536,8 @@ func (session *Session) dropAll() error {
 	for _, table := range session.Engine.Tables {
 		session.Statement.Init()
 		session.Statement.RefTable = table
-		err := session.Engine.Dialect().MustDropTable(session.Statement.TableName())
-		//sqlStr := session.Statement.genDropSQL()
-		//_, err := session.exec(sqlStr)
+		sqlStr := session.Engine.Dialect().DropTableSql(session.Statement.TableName())
+		_, err := session.exec(sqlStr)
 		if err != nil {
 			return err
 		}