dbms_lob.append 无法将字符串附加到绑定变量

Question

有人能指出我在这里遗漏了什么吗？

下面是一个最小的例子：

var c clob
exec dbms_lob.append(:c, 'test')
print c

它产生这个错误：

BEGIN dbms_lob.append(:c, 'test'); END;
Error report -
ORA-06502: PL/SQL: numeric or value error: invalid LOB locator specified: ORA-22275
ORA-06512: at "SYS.DBMS_LOB", line 656
ORA-06512: at line 1
06502. 00000 -  "PL/SQL: numeric or value error%s"
*Cause:    An arithmetic, numeric, string, conversion, or constraint error
           occurred. For example, this error occurs if an attempt is made to
           assign the value NULL to a variable declared NOT NULL, or if an
           attempt is made to assign an integer larger than 99 to a variable
           declared NUMBER(2).
*Action:   Change the data, how it is manipulated, or how it is declared so
           that values do not violate constraints.

我检查了Oracle文档关于绑定变量，它说

当您执行 VARIABLE ... CLOB 或 NCLOB 命令时，SQL*Plus 将 LOB 定位器与绑定变量相关联。

所以我不认为这是因为没有分配给

c

的定位器。

Answer 1

在像这样使用它之前，您需要“创建”lob。

SQL> var c clob
SQL> exec dbms_lob.createtemporary(:c,false);

PL/SQL procedure successfully completed.

SQL> exec dbms_lob.append(:c,'acb');

PL/SQL procedure successfully completed.

SQL> print :c

C
--------------------------------------------------------------------------------
acb