Calling a Function in a Database

最新推荐文章于 2024-12-17 16:08:23 发布

原创最新推荐文章于 2024-12-17 16:08:23 发布 · 445 阅读

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文章标签：

#function #database #string #parameters #types

本文介绍如何使用Java通过CallableStatement调用带有IN、OUT和IN/OUT参数的存储过程。具体包括：无参数存储过程返回VARCHAR类型的值；带有单个IN参数的存储过程返回VARCHAR类型值；带有单个OUT参数的存储过程返回VARCHAR类型值；带有单个IN/OUT参数的存储过程返回VARCHAR类型值。

A function is essentially a stored procedure that returns a result. This example demonstrates how to call functions with IN, OUT, and IN/OUT parameters.

    CallableStatement cs;
    try {
      // Call a function with no parameters; the function returns a VARCHAR
        // Prepare the callable statement
        cs = connection.prepareCall("{? = call myfunc}");
    
        // Register the type of the return value
        cs.registerOutParameter(1, i);
    
        // Execute and retrieve the returned value
        cs.execute();
        String retValue = cs.getString(1);
    
      // Call a function with one IN parameter; the function returns a VARCHAR
        cs = connection.prepareCall("{? = call myfuncin(?)}");
    
        // Register the type of the return value
        cs.registerOutParameter(1, Types.VARCHAR);
    
        // Set the value for the IN parameter
        cs.setString(2, "a string");
    
        // Execute and retrieve the returned value
        cs.execute();
        retValue = cs.getString(1);
    
      // Call a function with one OUT parameter; the function returns a VARCHAR
        cs = connection.prepareCall("{? = call myfuncout(?)}");
    
        // Register the types of the return value and OUT parameter
        cs.registerOutParameter(1, Types.VARCHAR);
        cs.registerOutParameter(2, Types.VARCHAR);
    
        // Execute and retrieve the returned values
        cs.execute();
        retValue = cs.getString(1);           // return value
        String outParam = cs.getString(2);    // OUT parameter
    
      // Call a function with one IN/OUT parameter; the function returns a VARCHAR
        cs = connection.prepareCall("{? = call myfuncinout(?)}");
    
        // Register the types of the return value and OUT parameter
        cs.registerOutParameter(1, Types.VARCHAR);
        cs.registerOutParameter(2, Types.VARCHAR);
    
        // Set the value for the IN/OUT parameter
        cs.setString(2, "a string");
    
        // Execute and retrieve the returned values
        cs.execute();
        retValue = cs.getString(1);           // return value
        outParam = cs.getString(2);           // IN/OUT parameter
    } catch (SQLException e) {
    }