优化n^2循环内的合并查询

Question

我有一个合并查询，需要对request ArrayList中的day和sessionType的每个组合执行一次。我正在使用nativeQuery来执行它。

MERGE INTO TABLE_A A
    USING 
    (
    SELECT
    :description AS DESCRIPTION,
    :sessionType AS SESSION_TYPE,
    :day AS DAY,
    :flag1 AS FLAG1,
    :flag2 AS FLAG2,
    FROM DUAL) AS SOURCE
    ON (SOURCE.DESCRIPTION=
        A.DESCRIPTION AND SOURCE.DAY=
        A.DAY
        )
    WHEN MATCHED THEN
        UPDATE SET 
        FLAG1=SOURCE.FLAG1,
        FLAG2=SOURCE.FLAG2  
    WHEN NOT MATCHED THEN
        INSERT (
        DESCRIPTION,
        SESSION_TYPE,
        DAY,
        FLAG1,
        FLAG2
        )
        VALUES (
        SOURCE.DESCRIPTION,
        SOURCE.SESSION_TYPE,
        SOURCE.DAY,
        SOURCE.FLAG1,
        SOURCE.FLAG2    
        );

Answer 1

>

您可以使用executebatch:在这种情况下，oracle会自动在输入数组上执行sql语句

您可以绑定一个集合并在table()中使用它，如下所示：

MERGE INTO TABLE_A A
    USING 
    (
    SELECT *
    FROM table(:bind_collection)
    ) AS SOURCE
    ON (SOURCE.DESCRIPTION=
        A.DESCRIPTION AND SOURCE.DAY=
        A.DAY
        )
    WHEN MATCHED THEN
        UPDATE SET 
        FLAG1=SOURCE.FLAG1,
        FLAG2=SOURCE.FLAG2  
    WHEN NOT MATCHED THEN
    ...