我使用HSQLDB和preparedStatements很好,但是如果我在SQL语句中包含“SELECT TOP”或“ORDER BY”,当我调用updateBoolean(或UpdateInt等)时,我会遇到异常:
java.sql.SQLException: attempt to assign to non-updatable column
此示例代码运行良好:
preparedStatement = connection.prepareUpdatable(
"SELECT " + MyTable.COL_ID + ", " +
MyTable.COL_READ +
" FROM " + MyTable.NAME +
" WHERE " + MyTable.COL_LOCAL +
" =? AND " + MyTable.COL_REMOTE +
" =?",
ResultSet.TYPE_FORWARD_ONLY,
ResultSet.CONCUR_UPDATABLE);
preparedStatement.setString(1, localAddress);
preparedStatement.setString(2, remoteAddress);
ResultSet rs = connection.query(preparedStatement);
if (rs.next())
{
rs.updateBoolean(MyTable.COL_READ, isRead);
rs.updateRow();
}
如果我将“SELECT”更改为“SELECT TOP”,则会出现异常。或者如果我将其附加到 SQL 语句中:
" ORDER BY " + MyTable.COL_RECEIVED_TIMESTAMP + " DESC"
感谢您的帮助。
尼克B
最佳答案
可更新的 SELECT 语句不能包含 TOP n
、LIMIT
或 ORDER BY
。此限制是由 SQL 标准强加的。当您添加这些关键字之一时,您的 SELECT 将变得不可更新。
可以在带有上述关键字的WITH子句中使用子查询,并且SELECT是可更新的。
CREATE TABLE t (a int, b int, PRIMARY KEY(a));
WITH SUBQ(COL) AS (SELECT TOP 1 a FROM t)
SELECT * FROM t WHERE a IN (SELECT * FROM SUBQ)
关于HSQLDB - 可更新语句不适用于 "SELECT TOP"或 "ORDER BY",我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35163880/