从Oracle存储过程返回XML

Question

不幸的是,我的数据库经验一直是MSSQL,它往往比Oracle更耐心.我想要做的是在tSQL中相当微不足道,然而,pl/sql让我很头疼.

我有以下程序:

    CREATE OR REPLACE PROCEDURE USPX_GetUserbyID (USERID USERS.USERID%TYPE, USERRECORD OUT XMLTYPE) AS
BEGIN

    SELECT XMLELEMENT("user"
        , XMLATTRIBUTES(u.USERID AS "userid", u.companyid as "companyid", u.usertype as "usertype", u.status as "status", u.personid as "personid")
        , XMLFOREST(  p.FIRSTNAME AS "firstname"
                    , p.LASTNAME AS "lastname"
                    , p.EMAIL AS "email"
                    , p.PHONE AS "phone"
                    , p.PHONEEXTENSION AS "extension")
        ,  XMLELEMENT("roles",
                (SELECT XMLAGG(XMLELEMENT("role", r.ROLETYPE))
                    FROM USER_ROLES r
                    WHERE r.USERID = USERID
                        AND r.ISACTIVE = 1
                )
            )
        , XMLELEMENT("watches",
                (SELECT XMLAGG(
                    XMLELEMENT("watch",
                        XMLATTRIBUTES(w.WATCHID AS "id", w.TICKETID AS "ticket")
                    )
                )
                FROM USER_WATCHES w
                WHERE w.USERID = USERID
                AND w.ISACTIVE = 1
                )
            )
        ) AS "RESULT"
    INTO USERRECORD
    FROM USERS u 
    LEFT JOIN PEOPLE p ON p.PERSONID = u.PERSONID
    WHERE u.USERID = USERID;
    END USPX_GetUserbyID;

执行时,它应返回具有以下结构的XML文档:

<user userid="" companyid="" usertype="" status="" personid="">
    <firstname />
    <lastname />
    <email />
    <phone />
    <extension />
    <roles>
        <role />
    </roles>
    <watches>
        <watch id="" ticket="" />
    </watches>
</user>

当我执行查询本身,用字符串替换USERID参数并删除"into"子句时,查询运行正常并返回预期的结构.

但是,当该过程尝试执行查询时,将XMLELEMENT函数的结果传递给USERRECORD输出参数,我得到以下异常:

Error report: ORA-01422: exact fetch returns more than requested number of rows ORA-06512: at "USPX_GETUSERBYID", line 4 ORA-06512: at line 3
01422. 00000 -  "exact fetch returns more than requested number of rows"
*Cause:    The number specified in exact fetch is less than the rows returned.
*Action:   Rewrite the query or change number of rows requested

我很困惑,试图解决这个问题,不幸的是我的google-fu没有帮助.我发现了大量的Oracle SQL | XML示例,但没有一个处理XML的过程返回.

注意:我知道存在使用DBMS方法检索XML的替代方法,但是,我的理解是不推荐使用该功能而使用SQL | XML.

Answer 1

您的代码包括以下内容:

u.USERID = USERID;

虽然您希望将裸USERID作为过程的参数,但Oracle实际上优先考虑表中列的USERID.实际上它将其解释为

u.USERID = u.USERID;

您可以使用

u.USERID = USPX_GetUserbyID.USERID;

但最好使用PL/SQL变量的前缀来避免混淆.我倾向于v_表示变量,而i_,o_,io_表示输入,输出和输入/输出参数.