经常和oracle打交道的人都应该遇到会遇到过这么一类需求：

1. 哪些表引用了这个表

2. 这条数据被引用了几次

3. 这张表引用了哪些表，引用的字段是什么

本人也经常遇到这些问题，特别是当删除一条数据总是被告知被引用的时候。于是写了以下外键反查套件：

注： 本套件只支持表中主键列名为ID，ID为NUMBER类型，如果不符合你的需求可自行修改。

用法

• 查询我引用谁

  SELECT * FROM TABLE(FK_UTIL.get_refering_stats('TABLE_A'));

• 查询谁引用我

  SELECT * FROM TABLE(FK_UTIL.get_refered_stats('TABLE_A'));

• 查询ID为的某条记录的被引用计数

  SELECT * FROM TABLE(FK_UTIL.get_refered_count('TABLE_A',ID));

• 查询某种条件下的被引用计数

  -- 查询code为1的某条记录的被引用计数
  SELECT * FROM TABLE(FK_UTIL.get_refered_count_cond('xb_std_types','code','1'));

• 查询某表在某种条件下的被引用情况，并且附带出更详细的信息

  SELECT TABLE_A.id,TABLE_A.COLUMN1,TABLE_A.COLUMN2,...,stats.child_table,stats.refer_count
  FROM TABLE_A 
  JOIN TABLE(FK_UTIL.get_refered_count_cond('TABLE_A','COLUMN','VALUE')) stats
  ON stats.parent_id=TABLE_A.id;

安装

执行下列sql语句，安装本套件

CREATE OR REPLACE TYPE fk_stats_row AS object (
  child_table             varchar2(32),child_table_fk_col    varchar2(32),parent_table             varchar2(32),parent_table_pk_col   varchar2(32)
);
/
 
CREATE OR REPLACE TYPE fk_stats AS TABLE OF fk_stats_row;
/
 
CREATE OR REPLACE TYPE fk_refered_count_row AS object (
  child_table             varchar2(32),parent_id                NUMBER(19),refer_count            NUMBER(19)
);
/
 
CREATE OR REPLACE TYPE fk_refered_count AS TABLE OF fk_refered_count_row;
/
 
CREATE OR REPLACE TYPE id_array AS TABLE OF NUMBER(19);
/
 
CREATE OR REPLACE package FK_UTIL
IS 
    -- 获得我所引用的表
    FUNCTION get_refering_stats(v_table_name varchar2) RETURN fk_stats;
    -- 获得所有子表及外键列
    FUNCTION get_refered_stats(v_table_name varchar2) RETURN fk_stats;
    -- 获得所有子表对某个ID的引用条数
    FUNCTION get_refered_count(v_parent_table varchar2,v_parent_id NUMBER) RETURN fk_refered_count;
    -- 获得所有子表对符合条件的某些记录的引用条数
    FUNCTION get_refered_count_cond(v_parent_table varchar2,v_cond_col varchar2,v_cond varchar2) RETURN fk_refered_count;
END FK_UTIL;
/
 
CREATE OR REPLACE package body FK_UTIL
IS
    -- 获得我所引用的表
    FUNCTION get_refering_stats(v_table_name varchar2) RETURN fk_stats
    IS
        v_ret fk_stats := fk_stats();
    BEGIN
        SELECT CAST(
            multiset(
                SELECT a.TABLE_NAME 从表,a.column_name 外键列,b.TABLE_NAME 主表,b.column_name 被引用列
                FROM (
                    SELECT     uc.TABLE_NAME,ucc.column_name,uc.r_constraint_name
                    FROM     user_constraints uc 
                    JOIN     user_cons_columns ucc
                    ON     uc.constraint_name = ucc.constraint_name
                    WHERE uc.constraint_type='R'
                    ) a,(
                    SELECT     uc.TABLE_NAME,uc.constraint_name 
                    FROM     user_constraints uc 
                    JOIN    user_cons_columns ucc
                    ON    uc.constraint_name = ucc.constraint_name
                    ) b
                WHERE
                    a.r_constraint_name = b.constraint_name
                    AND a.TABLE_NAME = UPPER(v_table_name)
            ) AS fk_stats
        ) INTO v_ret FROM dual;
        RETURN v_ret;
    END get_refering_stats;
 
    -- 获得所有子表及外键列
    FUNCTION get_refered_stats(v_table_name varchar2) RETURN fk_stats
    IS
        v_ret fk_stats := fk_stats();
    BEGIN
        SELECT CAST(
            multiset(
                SELECT a.TABLE_NAME 从表,uc.constraint_name 
                    FROM     user_constraints uc 
                    JOIN    user_cons_columns ucc
                    ON    uc.constraint_name = ucc.constraint_name
                    ) b
                WHERE
                    a.r_constraint_name = b.constraint_name
                    AND b.TABLE_NAME = UPPER(v_table_name)
            ) AS fk_stats
        ) INTO v_ret FROM dual;
        RETURN v_ret;
    END get_refered_stats;
 
    -- 获得所有子表对某个ID的引用条数
    FUNCTION get_refered_count(v_parent_table varchar2,v_parent_id NUMBER) RETURN fk_refered_count
    IS
        v_ret fk_refered_count := fk_refered_count();
        v_count NUMBER := 0;
        v_sql varchar2(2000) := '';
    BEGIN
        FOR v_row IN (SELECT * FROM TABLE(get_refered_stats(v_parent_table))) loop
            v_sql := 'select count(*) from '|| v_row.child_table ||' where ' || v_row.child_table_fk_col || ' = ' || v_parent_id;
            EXECUTE immediate v_sql INTO v_count;
            v_ret.extend(1);
            v_ret(v_ret.COUNT) := fk_refered_count_row(v_row.child_table,v_parent_id,v_count);
        END loop;
        RETURN v_ret;
    END get_refered_count;
    -- 获得所有子表对符合条件的某些记录的引用条数
    FUNCTION get_refered_count_cond(v_parent_table varchar2,v_cond varchar2) RETURN fk_refered_count
    IS
        v_ret fk_refered_count := fk_refered_count();
        v_id_array id_array := id_array();
        v_sql varchar2(2000) := '';
    BEGIN
        IF UPPER(v_cond_col) LIKE '%ID' THEN
            v_sql := 'select cast(multiset(select id from ' || v_parent_table || ' where '|| v_cond_col ||'=' || v_cond || ') as id_array) from dual';
        ELSE
            v_sql := 'select cast(multiset(select id from ' || v_parent_table || ' where '|| v_cond_col ||'=''' || v_cond || ''') as id_array) from dual';
        END IF;
        EXECUTE immediate v_sql INTO v_id_array;
        FOR id_row IN (SELECT * FROM TABLE(v_id_array)) loop
            FOR count_row IN (SELECT * FROM TABLE(get_refered_count(v_parent_table,id_row.column_value))) loop
                v_ret.extend(1);
                v_ret(v_ret.COUNT) := fk_refered_count_row(count_row.child_table,count_row.parent_id,count_row.refer_count);
            END loop;
        END loop;
        RETURN v_ret;
    END get_refered_count_cond;
END FK_UTIL;
/