Question

当我们无法更改游标数量时，避免ORA-0100: Maximum open cursors exceeded的最佳方法是什么？

有没有比下面更好的方式：

Connection connection = DriverManager.getConnection(/* Oracle Driver */);
Statement st = null;
  st = connection.createStatement();
for (/* a lot of iteration with counter */) {

  st.executeUpdate(insertSql);

  if ( counter % 500 == 0) {
    st.close();
    connection.commit();
    st = connection.createStatement();
  }
}

哪个方法调用消耗光标：到executeUpdate或createStatement？
我认为这是executeUpdate方法，这就是我制作这个计数器的原因。

对于我工作的Oracle：

select * from v$version;

结果：

BANNER
----------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
PL/SQL Release 11.2.0.1.0 - Production
CORE 11.2.0.1.0 Production
TNS for 32-bit Windows: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production

Answer 1

您只关闭每个第50个声明......

for (/* a lot of iteration with counter */) {
  st = connection.createStatement(); //you create a statement each iteration!

  //...

  // This whole thing not right here
  if ( counter % 50 == 0) {
    st.close(); // not right here -- will have 49 open statements by now
    connection.commit(); //this too
  }

}

您应该使用预准备语句，并批量插入此数据量。

 PreparedStatement statement = connection.prepareStatement(insertTableSQL);
 for(<the objects you have>) {

   //set parameters into insert query
   statement.set*.*(1, <paramValue>);

   statement.addBatch(); //add it to the batch
 }

 statement.executeBatch();//execute whole batch
 connection.commit();

Answer 2

您只需要一个语句用于所有操作，因此您可以在循环外创建语句。

Connection connection = DriverManager.getConnection(/* Oracle Driver */);
Statement statement = connection.createStatement();
for (/* a lot of iteration with counter */) {
  // do some INSERT, SELECT, UPDATE
}
statement.close();
connection.close();

现在，在循环内部，您可以运行查询，例如：

statement.executeUpdate("query");

如何管理数百个插入？

2 个答案: