为什么 regexp_replace 没有用某些东西代替任何东西？

Question

我必须更新几个脚本才能使用另一个模式中的 table： S1.MYTABLE => S2.MYTABLE2.

另外，当我替换 table 的名称时，我想保留原始脚本的格式。如果在 S1.MYTABLE

之后有一个，则在 S2.MYTABLE2 之后保持输入或 space

我的代码似乎工作正常，但在字符串的末尾连接 S2.MYTABLE2.

这是我的测试脚本：（这只是我的问题的简化示例）

DECLARE
   testtext VARCHAR2(2000) := 'CREATE OR REPLACE FUNCTION "S1"."MY_FUNCTION" (PARAMETER1 VARCHAR2)
   RETURN VARCHAR2
AS
   something1    VARCHAR2 (50);
   OUTsomething   VARCHAR2 (50);
BEGIN
   BEGIN
      SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE_RELATED
       WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE
       WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;

   SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE                                  
        WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;
END;';

   script CLOB;
   owner VARCHAR2(30) := 'S1';
   object_name VARCHAR2(30) := 'MYTABLE';
   output_name VARCHAR2(30) := 'MYTABLE2';
   destination VARCHAR2(30) := 'S2';

BEGIN

        script := regexp_replace(testtext, OWNER || '[[:space:]]*\.[[:space:]]*' || OBJECT_NAME || ' ', DESTINATION || '.' || OUTPUT_NAME || ' ',1, 0, 'i');
        script := regexp_replace(script, OWNER || '[[:space:]]*\.[[:space:]]*' || OBJECT_NAME || '\s|($)', DESTINATION || '.' || OUTPUT_NAME || CHR(13) || CHR(10),1, 0, 'i');                
        DBMS_OUTPUT.PUT_LINE(script);                    
END;

函数的代码MY_FUNCTION，虽然不切实际，但举例说明了我正在处理的所有情况。

运行这个脚本的结果：

CREATE OR REPLACE FUNCTION "S1"."MY_FUNCTION" (PARAMETER1 VARCHAR2)
   RETURN VARCHAR2
AS
   something1    VARCHAR2 (50);
   OUTsomething   VARCHAR2 (50);
BEGIN
   BEGIN
      SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE_RELATED
       WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S2.MYTABLE2
       WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S2.MYTABLE2 WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;

   SELECT COLUMN1
        INTO OUTsomething
        FROM S2.MYTABLE2                                  
        WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;
END;S2.MYTABLE2

如您所见，S1.MYTABLE 已在所有相关位置替换为 S2.MYTABLE2，保持原来的格式（spaces 并输入）。

但由于某些原因 S2.MYTABLE2 被连接在最后。

为什么 regexp_replace 在脚本末尾连接 S2.MYTABLE2？

有没有更好的方法来实现我想要的？ 将 table 替换为另一个，保持格式。

Answer 1

这是问题所在：

\s|($)

这表示交替匹配，最终将用新文本替换字符串锚点的结尾。我想你想要这个：

(\s|$)

Answer 2

可能是因为第二个正则表达式中的|($)。不确定你为什么想要它。

关于删除 -

DECLARE
   testtext      VARCHAR2 (2000)
      := 'CREATE OR REPLACE FUNCTION "S1"."MY_FUNCTION" (PARAMETER1 VARCHAR2)
   RETURN VARCHAR2
AS
   something1    VARCHAR2 (50);
   OUTsomething   VARCHAR2 (50);
BEGIN
   BEGIN
      SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE_RELATED
       WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE
       WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;

   SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE                                  
        WHERE COLUMN2 = ''xx'' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;
END;';

   script        CLOB;
   owner         VARCHAR2 (30) := 'S1';
   object_name   VARCHAR2 (30) := 'MYTABLE';
   output_name   VARCHAR2 (30) := 'MYTABLE2';
   destination   VARCHAR2 (30) := 'S2';
BEGIN
   script      :=
      REGEXP_REPLACE (
         testtext,
         OWNER || '[[:space:]]*\.[[:space:]]*' || OBJECT_NAME || ' ',
         DESTINATION || '.' || OUTPUT_NAME || ' ',
         1,
         0,
         'i');
   script      :=
      REGEXP_REPLACE (
         script,
         OWNER || '[[:space:]]*\.[[:space:]]*' || OBJECT_NAME || '\s',
         DESTINATION || '.' || OUTPUT_NAME || CHR (13) || CHR (10),
         1,
         0,
         'i');
   DBMS_OUTPUT.PUT_LINE (script);
END;

这是末尾没有 table 名称的输出 -

CREATE OR REPLACE FUNCTION "S1"."MY_FUNCTION" (PARAMETER1 VARCHAR2)
   RETURN VARCHAR2
AS
   something1    VARCHAR2 (50);
   OUTsomething   VARCHAR2 (50);
BEGIN
   BEGIN
      SELECT COLUMN1
        INTO OUTsomething
        FROM S1.MYTABLE_RELATED
       WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S2.MYTABLE2
       WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;

       SELECT COLUMN1
        INTO OUTsomething
        FROM S2.MYTABLE2 WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;

   SELECT COLUMN1
        INTO OUTsomething
        FROM S2.MYTABLE2                                  
        WHERE COLUMN2 = 'xx' AND COLUMN2 = PARAMETER1;                                           
   RETURN OUTsomething;
END;

编辑：如果您的正则表达式模式也可能出现在整个字符串的末尾（而不仅仅是一行的末尾），您可能需要按照@DavidFaber 的回答进行操作。

为什么 regexp_replace 没有用某些东西代替任何东西？

Why does regexp_replace replaces nothing with something?

regex

oracle

oracle10g