oracle DB - PLSQL 函数中的 Clob 冲突

Question

你好，我设计了这张桌子：

CREATE TABLE "PUBLIC"."FORMS_UNITS" 
   (    "CODE" VARCHAR2(1024 BYTE) NOT NULL ENABLE, 
    "SUBTITLE" VARCHAR2(1024 BYTE), 
    "DESCRIPTION" CLOB, 
    "ELEMENTS" CLOB NOT NULL ENABLE, 
    "STATUS" VARCHAR2(1024 BYTE) DEFAULT 'Borrador' NOT NULL ENABLE, 
    "KEYWORDS" VARCHAR2(1024 BYTE), 
    "CREATED_AT" TIMESTAMP (6), 
    "UPDATED_AT" TIMESTAMP (6), 
    "CREATED_BY" NUMBER(19,0) NOT NULL ENABLE, 
    "UPDATED_BY" NUMBER(19,0), 
     CONSTRAINT "FORMS_UNITS_ID_PK" PRIMARY KEY ("CODE")
  USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS 
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "APPSDATA"  ENABLE, 
     CONSTRAINT "FORMS_UNITS_USER_CB_ID_FK" FOREIGN KEY ("CREATED_BY")
      REFERENCES "PUBLIC"."USERS" ("ID") ON DELETE CASCADE ENABLE, 
     CONSTRAINT "FORMS_UNITS_USER_uB_ID_FK" FOREIGN KEY ("UPDATED_BY")
      REFERENCES "PUBLIC"."USERS" ("ID") ON DELETE CASCADE ENABLE
   ) SEGMENT CREATION IMMEDIATE 
  PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255 
 NOCOMPRESS LOGGING
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  TABLESPACE "APPSDATA" 
 LOB ("DESCRIPTION") STORE AS BASICFILE (
  TABLESPACE "APPSDATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION 
  NOCACHE LOGGING 
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)) 
 LOB ("ELEMENTS") STORE AS BASICFILE (
  TABLESPACE "APPSDATA" ENABLE STORAGE IN ROW CHUNK 8192 RETENTION 
  NOCACHE LOGGING 
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1
  BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)) ;

问题出在以下 plsql 函数中，它返回此错误：

SQL 错误：ORA-06502：PL/SQL：数字或值错误 ORA-06512：在 “PUBLIC.FORMS_PKG”，第 315 行 06502. 00000 - “PL/SQL：数字或值错误%s” *原因：算术、数字、字符串、转换或约束错误 发生。例如，如果尝试执行以下操作，则会出现此错误 将值 NULL 赋给声明为 NOT NULL 的变量，或者如果 尝试将大于 99 的整数分配给变量 声明为 NUMBER(2)。 *操作：更改数据、其操作方式或声明方式 该值不违反约束。

这是 PLSQL 函数：

FUNCTION GET_FORMS
RETURN CLOB
AS
     l_query      CLOB;
     l_result     CLOB;
     l_temp       SYS_REFCURSOR;
     l_row        FORMS_UNITS%ROWTYPE;
BEGIN
    l_query := 'SELECT CODE, TITLE, SUBTITLE, DESCRIPTION, KEYWORDS, ELEMENTS, STATUS, CREATED_AT, UPDATED_AT, CREATED_BY, UPDATED_BY  FROM FORMS_UNITS';    
    OPEN l_temp FOR l_query;
    l_result := '[ ';
    LOOP
        FETCH l_temp INTO l_row;
        EXIT WHEN l_temp%NOTFOUND;
        l_result := l_result || '{ "CODE": "' || l_row.CODE || '", "TITLE": "' || l_row.TITLE || '", "SUBTITLE": "' || l_row.SUBTITLE || '", "DESCRIPTION": "' || l_row.DESCRIPTION || '", "KEYWORDS": "' || l_row.KEYWORDS || '", "ELEMENTS": "' || l_row.ELEMENTS || '", "STATUS": "' || l_row.STATUS || '", "CREATED_AT": "' || l_row.CREATED_AT || '", "UPDATED_AT": "' || l_row.UPDATED_AT || '", "CREATED_BY": "' || l_row.CREATED_BY || '", "UPDATED_BY": "' || l_row.UPDATED_BY || '" }, ';
    END LOOP;
    IF l_temp%ISOPEN THEN
        CLOSE l_temp;
    END IF;
    l_result := RTRIM(l_result, ', ') || ' ]';

    RETURN l_result;
END;

问题似乎出在 FETCH l_temp INTO l_row; 线上；

由于问题出在表格组件元素上，导致CL.OB变量大小不足。当函数返回的内容长度为 4,959 个字符时，就会出现问题。现在，如果我减小大小，函数将返回正确的值。

Answer 1

如果您使用的是 Oracle 12 或更高版本，那么您不应该尝试手动生成 JSON；你应该使用内置的 JSON 函数：

FUNCTION GET_FORMS
RETURN CLOB
AS
     l_result     CLOB;
BEGIN
  SELECT JSON_ARRAYAGG(
           JSON_OBJECT(
             KEY 'CODE' VALUE CODE,
             -- KEY 'TITLE' VALUE TITLE, -- The table has no TITLE column
             KEY 'SUBTITLE' VALUE SUBTITLE,
             KEY 'DESCRIPTION' VALUE DESCRIPTION,
             KEY 'KEYWORDS'    VALUE KEYWORDS,
             KEY 'ELEMENTS'    VALUE ELEMENTS,
             KEY 'STATUS'      VALUE STATUS,
             KEY 'CREATED_AT'  VALUE TO_CHAR(CREATED_AT, 'YYYY-MM-DD"T"HH24:MI:SS.FF6'),
             KEY 'UPDATED_AT'  VALUE TO_CHAR(UPDATED_AT, 'YYYY-MM-DD"T"HH24:MI:SS.FF6'),
             KEY 'CREATED_BY'  VALUE CREATED_BY,
             KEY 'UPDATED_BY'  VALUE UPDATED_BY
             RETURNING CLOB
           )
           RETURNING CLOB
         )
  INTO   l_result
  FROM   FORMS_UNITS;

  RETURN l_result;
END;
/

小提琴