Oracle 函数 “判断数据表中不存在的数据，才允许通过”

 1 create or replace function mca_detail_material_val(p_material_code VARCHAR2,  --实参
 2                                                    p_material_name VARCHAR2,
 3                                                    p_mca_no VARCHAR2
 4                                                   ) 
 5        RETURN varchar2 AS
 6        
 7  --物料编码/名称的验证，数据表（MATERIAL）中 不存在 该物料编码/名称，允许通过，填其他值都不允许通过
 8 
 9        v_count1   NUMBER; -- 形参
10        v_count2   NUMBER;
11        v_count3   NUMBER;
12        v_count4   NUMBER;
13 
14        CURSOR get_wl_material_code1 IS
15               SELECT count(m.material_code)  -- count()函数：查询出来的记录条数（记录数）
16               FROM   MATERIAL m
17               WHERE  m.material_code = p_material_code;
18               
19        CURSOR get_wl_material_code2 IS
20               SELECT count(material_code)
21               FROM   mca_detail m
22               WHERE  m.material_code = p_material_code AND m.mca_no <> p_mca_no;
23                                                      -- m.mca_no <> p_mca_no:在编辑时，排除此单号(不做比较)---物料编码
24        CURSOR get_wl_material_name1 IS
25               SELECT count(m.material_name)
26               FROM   MATERIAL m 
27               WHERE  m.material_name = p_material_name;
28               
29        CURSOR get_wl_material_name2 IS
30               SELECT count(m.material_name)
31               FROM   mca_detail m
32               WHERE  m.material_name = p_material_name AND m.mca_no <> p_mca_no;
33 BEGIN                                                -- m.mca_no <> p_mca_no:在编辑时，排除此单号(不做比较)---物料名称
34       OPEN get_wl_material_code1;
35       FETCH get_wl_material_code1 INTO v_count1;
36       CLOSE get_wl_material_code1;
37       
38       OPEN get_wl_material_code2;
39       FETCH get_wl_material_code2 INTO v_count3;
40       CLOSE get_wl_material_code2;
41       
42       OPEN get_wl_material_name1;
43       FETCH get_wl_material_name1 INTO v_count2;
44       CLOSE get_wl_material_name1;
45       
46       OPEN get_wl_material_name2;
47       FETCH get_wl_material_name2 INTO v_count4;
48       CLOSE get_wl_material_name2;
49 
50       IF v_count1+v_count3 <> 0 THEN
51          RETURN ‘4823272‘; -- 错误信息码（信息码表）,物料编码已存在，不允许出现相同值！
52       ELSIF v_count2+v_count4 <> 0 THEN
53          RETURN ‘4823273‘; -- 错误信息码（信息码表）,物料名称已存在，不允许出现相同值！
54       END IF;
55 
56       RETURN ‘0‘;
57 
58 end mca_detail_material_val;