SQL错误: ORA-00907:缺少右括号

Question

CREATE TABLE ADMIN (
    A_EMP_ID                   CHAR 5 BYTE                            NOT NULL,
    ADMIN_START_DATE           DATE                 DEFAULT SYSDATE       NOT NULL,
    ADMIN_END_DATE             DATE                                       NULL,
    DIVERSITY_TRAINING_CERT      CHAR(1 BYTE)       DEFAULT 'N'           NOT NULL,
    ADMIN_TITLE                  CHAR(40 BYTE)                            NULL,
    CONSTRAINT                   ADMIN_PK           PRIMARY KEY(A_EMP_ID),
  CONSTRAINT        ADMIN_FK1          
  FOREIGN KEY(A_EMP_ID)
  REFERENCES ADMIN(A_EMP_ID),
  CONSTRAINT                 ADMIN_DIVERSITY_CERT
      CHECK (DIVERSITY_TRAINING_CERT = 'N','Y'),
  CONSTRAINT                 ADMIN_END_DATE
      CHECK (<= 'ADMIN_START_DATE'),
    );



Error starting at line : 1 in command -
CREATE TABLE ADMIN (
    A_EMP_ID                   CHAR 5 BYTE                            NOT NULL,
    ADMIN_START_DATE           DATE                 DEFAULT SYSDATE       NOT NULL,
    ADMIN_END_DATE             DATE                                       NULL,
    DIVERSITY_TRAINING_CERT      CHAR(1 BYTE)       DEFAULT 'N'           NOT NULL,
    ADMIN_TITLE                  CHAR(40 BYTE)                            NULL,
    CONSTRAINT                   ADMIN_PK           PRIMARY KEY(A_EMP_ID),
  CONSTRAINT        ADMIN_FK1          
  FOREIGN KEY(A_EMP_ID)
  REFERENCES ADMIN(A_EMP_ID),
  CONSTRAINT                 ADMIN_DIVERSITY_CERT
      CHECK (DIVERSITY_TRAINING_CERT = 'N','Y'),
  CONSTRAINT                 ADMIN_END_DATE
      CHECK (<= 'ADMIN_START_DATE'),
    )
Error report -
SQL Error: ORA-00907: missing right parenthesis
00907. 00000 -  "missing right parenthesis"
*Cause:    
*Action:

上半部分是我的代码，当我运行它时，我从下半部分得到消息。我认为这与我的外键有关，但我不知道确切的解决方案是什么。任何帮助都是非常感谢的。

Answer 1

你的陈述有很多错误。

• A_EMP_ID CHAR 5 BYTE缺少长度约束周围的(..)
• 您绝对不想将CHAR用于admin_title。Use instead.
• DIVERSITY_TRAINING_CERT = 'N','Y' VARCHAR2不是有效的表达式。你可能希望diversity_training_cert IN ('N','Y')
• While FOREIGN KEY (a_emp_id) REFERENCES admin(a_emp_id)在语法上是正确的，这是没有意义的。我猜你想要一个manager_id或类似的东西。然后是像FOREIGN KEY (manager_id) REFERENCES admin(a_emp_id)这样的东西。

或者，您可能打算引用一个employee表。在这种情况下，table.

• CONSTRAINT ADMIN_END_DATE CHECK (<= 'ADMIN_START_DATE'),具有三个错误的a_emp_id数据类型必须与PK列的类型匹配：

- a column must not be enclosed in single quotes. So it has to be `admin_start_date` not `'admin_start_date'`
- a check constraint requires a proper condition. `<= admin_start_date` is not a condition, you need to compare the column it with something. Presumable `admin_end_date` 
- you have a comma `,` after that expression which is wrong as well.

​

把所有这些放在一起，你就会得到：

CREATE TABLE admin 
(
    a_emp_id                  CHAR(5 BYTE) NOT NULL, 
    admin_start_date          DATE DEFAULT SYSDATE NOT NULL,
    admin_end_date            DATE NULL,
    diversity_training_cert   CHAR(1 BYTE)  DEFAULT 'N' NOT NULL,
    admin_title               VARCHAR2(40 BYTE) NULL,
    CONSTRAINT admin_pk 
        PRIMARY KEY(a_emp_id),
    CONSTRAINT admin_fk1 
        FOREIGN KEY (a_emp_id) REFERENCES admin(a_emp_id),
    CONSTRAINT admin_diversity_cert 
        CHECK (diversity_training_cert IN ('N','Y')), 
    CONSTRAINT admin_end_date 
        CHECK ( admin_end_date <= admin_start_date) 
);

无关，但是:也绝对没有必要将所有内容都写成大写。

Answer 2

在最后一个括号前有一个待处理的逗号。

Answer 3

CHAR 5字节应该是CHAR (5字节)(但是无论如何都不应该使用CHAR，尝试VARCHAR2或NVARCHAR2...)

并且约束<= 'ADMIN_START_DATE‘不正确。它应该有两个要比较的值