通常我們在應用中對mysql執行了insert操作后,需要獲取插入記錄的自增主鍵,這時候通常用getGeneratedKeys()方法獲取主鍵
1. 獲得數據庫返回的主鍵
insert into book values(null,'編程珠璣',45);
2. 獲得主鍵的步驟
conn.prepareStatement(sql,autoGeneratedKeys)
autoGeneratedKeys是一個int值 ,1代表返回生成的主鍵,2代表不返回生成的主鍵;為了方便記憶,使用 Statement.Statement.RETURN_GENERATED_KEYS,Statement.NO_GENERATED_KEYS
3.獲得生成的主鍵
ResultSet rs=ps.getGeneratedKesy();
rs.next();
int userno= rs.getInt(1);
Statement stmt = null; ResultSet rs = null; try { stmt = conn.createStatement(java.sql.ResultSet.TYPE_FORWARD_ONLY, java.sql.ResultSet.CONCUR_UPDATABLE); // ... // 省略若干行(如上例般創建demo表) // ... stmt.executeUpdate( "INSERT INTO autoIncTutorial (dataField) " + "values ('Can I Get the Auto Increment Field?')", Statement.RETURN_GENERATED_KEYS); // 向驅動指明需要自動獲取generatedKeys! int autoIncKeyFromApi = -1; rs = stmt.getGeneratedKeys(); // 獲取自增主鍵! if (rs.next()) { autoIncKeyFromApi = rs.getInt(1); } else { // throw an exception from here } rs.close(); rs = null; System.out.println("Key returned from getGeneratedKeys():" + autoIncKeyFromApi); } finally { ... }