A、前的效率比后者高，在使用PreparedStatement对象执行SQL命令时，命令被数据库进行编译和解析，然后被放到命令缓冲区。
B、每当执行同一个PreparedStatement对象时，它就会被再解析一次，但不会被再次编译。在缓冲区中可以发现预编译的命令，并且可以重新使用。
C、如果要你写insert update delete 最好用preparedStatement，在有大量用户的企业级应用软件中，经常会重复执行相同的SQL命令.
D、使用PreparedStatement对象带来的编译次数的减少能够提高数据库的总体性能。
更多“以下关于statement， prestatement的区别不正确的是：（）”相关的问题
A、A.我们可以使用Class.forName或者DriverManager.registerDriver来注册给定的驱动driver B、B.PrepareStatement对象继承了Statement接口，但是访问数据库的速度并没有Statement对象快 C、C.Connection对象代表了和某一个数据源的连接 D、D.ResultSet对象负责处理数据结果集对象
A、Statement st=new Statement（） B、Statement st=cn.newStatement（） C、Statement st=cn.createNewStatement（） D、Statement st=cn.createStatement（）
A、可以使用Statement对象的executeQuery方法返回ResultSet对象 B、可以使用Connection对象的createStatement方法获得PreparedStatement对象 C、可以使用Connection对象的prepareCall（）方法获得CallableStatement对象 D、可以使用Connection对象的executeQuery方法返回ResultSet对象
A、A. The DESCRIBE DEPT statement displays the structure of the DEPT table. B、B. The ROLLBACK statement frees the storage space occupies by the DEPT table. C、C. The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist. D、D. The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.
A、A.All of the assert statements are used appropriately. B、B.Only the assert statement on line 12 is used appropriately. C、C.Only the assert statement on line 15 is used appropriately. D、D.Only the assert statement on line 18 is used appropriately. E、E.Only the assert statements on lines 12 and 15 are used appropriately. F、F.Only the assert statements on lines 12 and 18 are used appropriately. H、G.Only the assert statements on lines 15 and 18 are used appropriately.
A、in the INTO clause of an INSERT statement B、in the FROM clause of a SELECT statement C、in the GROUP BY clause of a SELECT statement D、in the WHERE clause of a SELECT statement E、in the SET clause of an UPDATE statement F、in the VALUES clause of an INSERT statement
A、in the INTO clause of an INSERT statement B、in the FROM clause of a SELECT statement C、in the GROUP BY clause of a SELECT statement D、in the WHERE clause of a SELECT statement E、in the SET clause of an UPDATE statement F、in the VALUES clause of an INSERT statement
A、The DESCRIBE DEPT statement displays the structure of the DEPT table. B、The ROLLBACK statement frees the storage space occupied by the DEPT table. C、The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist. D、The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.
A、The DESCRIBE DEPT statement displays the structure of the DEPT table. B、The ROLLBACK statement frees the storage space occupied by the DEPT table. C、The DESCRIBE DEPT statement returns an error ORA-04043: object DEPT does not exist. D、The DESCRIBE DEPT statement displays the structure of the DEPT table only if there is a COMMIT statement introduced before the ROLLBACK statement.
客服
TOP
查看正确答案
