Oracle中的关键字 保留字

Reserved words and keywordsare identifiers that have special meaning in PL/SQL.

You cannot use reserved words as ordinary user-defined identifiers. You can use them as quoted user-defined identifiers, but it is not recommended. For more information, see"QuotedUser-Defined Identifiers".

You can use keywords as ordinary user-defined identifiers,but it is not recommended.

不能使用保留字作为用户定义的变量。但是当加上双引号就可以，但是不推存。

关键字就可以作为用户定义的变量，但是不推存。

举例子：

（1）保留字

-- number

创建表，作为字段名。

SQL> CREATE TABLE cux_oyj_RESERVED_WORDS(NUMBER NUMBER);

CREATE TABLE cux_oyj_RESERVED_WORDS(NUMBER NUMBER)

ORA-00904: : 标识符无效

加上双引号，就可以

SQL> CREATE TABLE cux_oyj_RESERVED_WORDS("NUMBER" NUMBER);

Table created

但是查询：

SQL> SELECT rw.number from cux_oyj_RESERVED_WORDS rw;

SELECT rw.number from cux_oyj_RESERVED_WORDS rw

ORA-01747: user.table.column, table.column 或列说明无效

使用起来比较麻烦。

（2）关键字

--name

创建表，作为字段名。

SQL> CREATE TABLE cux_oyj_KEYWORDS(NAME VARCHAR2(50));

Table created

保留字与关键字的视图（动态视图）V$RESERVED_WORDS

This view gives a list of all SQL keywords. To determine whether a particular keyword is reserved in any way, check the RESERVED, RES_TYPE, RES_ATTR, and RES_SEMI columns.

保留字：

关键字：