如何从Java执行多个SQL语句 [英] How to execute multiple SQL statements from java

问题描述

我想一次执行多个查询或作业. 像这样 例如:

I want to execute the multiple queries or job in one execute. Something like this eg:

String query="select * from tab1;insert into tab1 values(...);update tab1..;delete from tab1...;"
Statement st = con1.createStatement();
ResultSet rs = st.executeQuery(query); 

或多个选择查询.查询将是动态的.

Or multiple select queries.Queries will be dynamic.

但是我无法执行此操作.以半冒号分隔的多个查询的运行方式是什么.

But I am not able to do this.What is the way to run multiple queries separated by semi colon.

推荐答案

您可以使用下面的示例使用addBatch& executeBatch命令可同时执行多个 SQL 命令.

you can achieve that using Following example uses addBatch & executeBatch commands to execute multiple SQL commands simultaneously.

批处理允许您将相关的SQL语句分组为批，然后通过一次调用将其提交到数据库. 参考

Batch Processing allows you to group related SQL statements into a batch and submit them with one call to the database. reference

一次将多个SQL语句发送到数据库时，可以减少通信开销，从而提高性能.

When you send several SQL statements to the database at once, you reduce the amount of communication overhead, thereby improving performance.

不需要
• JDBC驱动程序来支持此功能.您应该使用DatabaseMetaData.supportsBatchUpdates()方法来确定目标数据库是否支持批量更新处理.如果您的JDBC驱动程序支持此功能，则该方法返回true.
• Statement，PreparedStatement和CallableStatement的addBatch ()方法用于将单个语句添加到批处理中. executeBatch()用于开始执行所有分组在一起的语句.
• executeBatch ()返回一个整数数组，该数组的每个元素代表相应更新语句的更新计数.
• 就像您可以将语句添加到批处理中一样，您可以使用

• JDBC drivers are not required to support this feature. You should use the DatabaseMetaData.supportsBatchUpdates() method to determine if the target database supports batch update processing. The method returns true if your JDBC driver supports this feature.
• The addBatch() method of Statement, PreparedStatement, and CallableStatement is used to add individual statements to the batch. The executeBatch() is used to start the execution of all the statements grouped together.
• The executeBatch() returns an array of integers, and each element of the array represents the update count for the respective update statement.
• Just as you can add statements to a batch for processing, you can remove them with the clearBatch() method. This method removes all the statements you added with the addBatch() method. However, you cannot selectively choose which statement to remove.

示例:

import java.sql.*;

public class jdbcConn {
   public static void main(String[] args) throws Exception{
      Class.forName("org.apache.derby.jdbc.ClientDriver");
      Connection con = DriverManager.getConnection
      ("jdbc:derby://localhost:1527/testDb","name","pass");

      Statement stmt = con.createStatement
      (ResultSet.TYPE_SCROLL_SENSITIVE,
      ResultSet.CONCUR_UPDATABLE);
      String insertEmp1 = "insert into emp values
      (10,'jay','trainee')";
      String insertEmp2 = "insert into emp values
      (11,'jayes','trainee')";
      String insertEmp3 = "insert into emp values
      (12,'shail','trainee')";
      con.setAutoCommit(false);
      stmt.addBatch(insertEmp1);//inserting Query in stmt
      stmt.addBatch(insertEmp2);
      stmt.addBatch(insertEmp3);
      ResultSet rs = stmt.executeQuery("select * from emp");
      rs.last();
      System.out.println("rows before batch execution= "
      + rs.getRow());
      stmt.executeBatch();
      con.commit();
      System.out.println("Batch executed");
      rs = stmt.executeQuery("select * from emp");
      rs.last();
      System.out.println("rows after batch execution= "
      + rs.getRow());
   }
} 

引用 http://www.tutorialspoint.com/javaexamples/jdbc_executebatch.htm

这篇关于如何从Java执行多个SQL语句的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！