通过Oracle函数SQL实现C# String.Format字符串格式化功能

　　语言国际化要求，开发上要求Oracle数据库SQL中对应的返回信息-Message，实现一个通用函数调用，比如：提示信息内容：条码123456当前工站在FCT！”，即通用的信息内容格式化标准为：“条码{0}当前工站在{1}！”。

　　在C#代码中可以通过String.Format函数占位符替换的模式实现字符串格式化输出，Oracle中暂无此函数，所以可参考String.Format反编译的相应的逻辑去实现即可；

信息内容中多个参数，是以占位符{}来表示，多个参数则用数组；通过自定义数组类型（即Table表结构类型）.如下代码所示：

1 CREATE OR REPLACE TYPE stringarrary IS TABLE OF VARCHAR2 (4000);

FUNCTION---StringSplit（参数--信息内容，参数--分割符）

--分割函数CREATE OR REPLACE FUNCTION StringSplit (
SOURCE VARCHAR2, --信息内容
spliter VARCHAR2--分割符
)
   RETURN stringarrary
IS
   j             INT             := 0;
   i             INT             := 1;
   len           INT             := 0;
   len1          INT             := 0;
   str           VARCHAR2 (4000);
   returnvalue   stringarrary    := stringarrary ();
BEGIN
   IF (spliter IS NULL) OR (SOURCE IS NULL)
   THEN
      returnvalue.EXTEND;
      returnvalue (1) := SOURCE;
   ELSE
      len := LENGTH (SOURCE);
      len1 := LENGTH (spliter);

      WHILE j < len
      LOOP
         j := INSTR (SOURCE, spliter, i);

         IF j = 0
         THEN
            j := len;
            str := SUBSTR (SOURCE, i);
            returnvalue.EXTEND;
            returnvalue (returnvalue.COUNT) := str;

            IF i >= len
            THEN
               EXIT;
            END IF;
         ELSE
            str := SUBSTR (SOURCE, i, j - i);
            i := j + len1;
            returnvalue.EXTEND;
            returnvalue (returnvalue.COUNT) := str;
         END IF;
      END LOOP;
   END IF;

   RETURN returnvalue;
END stringsplit;

1 CREATE OR REPLACE FUNCTION stringsplit (SOURCE VARCHAR2, spliter VARCHAR2)
2    RETURN stringarrary
3 IS
4    j             INT             := 0;
5    i             INT             := 1;
6    len           INT             := 0;
7    len1          INT             := 0;
8    str           VARCHAR2 (4000);
9    returnvalue   stringarrary    := stringarrary ();
10 BEGIN
11    IF (spliter IS NULL) OR (SOURCE IS NULL)
12    THEN
13       returnvalue.EXTEND;
14       returnvalue (1) := SOURCE;
15    ELSE
16       len := LENGTH (SOURCE);
17       len1 := LENGTH (spliter);
18
19       WHILE j < len
20       LOOP
21          j := INSTR (SOURCE, spliter, i);
22
23          IF j = 0
24          THEN
25             j := len;
26             str := SUBSTR (SOURCE, i);
27             returnvalue.EXTEND;
28             returnvalue (returnvalue.COUNT) := str;
29
30             IF i >= len
31             THEN
32                EXIT;
33             END IF;
34          ELSE
35             str := SUBSTR (SOURCE, i, j - i);
36             i := j + len1;
37             returnvalue.EXTEND;
38             returnvalue (returnvalue.COUNT) := str;
39          END IF;
40       END LOOP;
41    END IF;
42
43    RETURN returnvalue;
44 END stringsplit;

1.分割函数测试如下：

 SELECT *
   FROM TABLE (CAST (StringSplit ('1|12|123|1234||12345|', '|') AS stringarrary));

测试结果：

             COLUMN_VALUE
               1
               12
               123
               1234

               12345

OK。

然后封装函数StringFormat：

CREATE OR REPLACE FUNCTION StringFormat (SOURCE     VARCHAR2,
                                          param      VARCHAR2,
                                          spliter    VARCHAR2)
   RETURN VARCHAR2
IS
   i             INT := 0;
   len           INT := 0;
   params        stringarrary := stringarrary ();
   returnvalue   VARCHAR2 (4000);
BEGIN
   params := stringsplit (param, spliter);

   IF params.COUNT > 0
   THEN
      len := params.COUNT;
      returnvalue := SOURCE;

      WHILE i < len
      LOOP
         returnvalue :=
            REPLACE (returnvalue,
                     CONCAT (CONCAT ('{', TO_CHAR (i)), '}'),
                     params (i + 1));
         i := i + 1;
      END LOOP;
   END IF;

   RETURN returnvalue;
END stringreplace;

1 CREATE OR REPLACE FUNCTION stringreplace (
2 SOURCE VARCHAR2,
3 param VARCHAR2,
4 spliter VARCHAR2
5 )
6 RETURN VARCHAR2
7 IS
8 i INT := 0;
9 len INT := 0;
10 params stringarrary := stringarrary ();
11 returnvalue VARCHAR2 (4000);
12 BEGIN
13 params := stringsplit (param, spliter);
14
15 IF params.COUNT > 0
16 THEN
17 len := params.COUNT;
18 returnvalue := SOURCE;
19
20 WHILE i < len
21 LOOP
22 returnvalue :=
23 REPLACE (returnvalue,
24 CONCAT (CONCAT ('{', TO_CHAR (i)), '}'),
25 params (i + 1)
26 );
27 i := i + 1;
28 END LOOP;
29 END IF;
30
31 RETURN returnvalue;
32 END stringreplace;

2.测试Oracle---StringFormat函数了。

SELECT StringFormat('条码{0}当前工站在{1}！', '123456|FCT', '|') FROM DUAL;

1 select stringreplace('{0}+{1}={0}{1}','吱吱|YY','|') from dual;

测试结果：

条码123456当前工站在FCT！