Question

我对数据库完全陌生，并且对Oracle语法有些困惑。我正在尝试创建一个具有完整性约束的表来伴随它。

这是我的代码：

   CREATE TABLE  Students 
( 
id                INTEGER, 
name              CHAR(10)    NOT NULL,  
classification    CHAR(10)    NOT NULL, 
hours             INTEGER, 
gpa               NUMBER(3,2) NOT NULL, 
mentor            INTEGER, 

CONSTRAINT IC1 CHECK (PRIMARY KEY (id))
CONSTRAINT IC2 CHECK (classification = 'freshman' or classification = 'sophomore' or classification = 'junior' or classification = 'senior')
CONSTRAINT IC3 CHECK (gpa >= 0 AND gpa <= 4) 
CONSTRAINT IC4 CHECK (classification = 'junior' AND hours >= 55 AND hours <= 84)  );

但是每当我运行代码时，我都会得到：

SQL> CONSTRAINT IC1 CHECK (PRIMARY KEY (id))
SP2-0734: unknown command beginning "CONSTRAINT..." - rest of line ignored.
SQL> CONSTRAINT IC2 CHECK (classification = 'freshman' or classification = 'sophomore' or classification = 'junior' or classification = 'senior')
SP2-0734: unknown command beginning "CONSTRAINT..." - rest of line ignored.
SQL> CONSTRAINT IC3 CHECK (gpa >= 0 AND gpa <= 4)
SP2-0734: unknown command beginning "CONSTRAINT..." - rest of line ignored.
SQL> CONSTRAINT IC4 CHECK (classification = 'junior' AND hours >= 55 AND hours <= 84)  );
SP2-0734: unknown command beginning "CONSTRAINT..." - rest of line ignored.
SP2-0044: For a list of known commands enter HELP
and to leave enter EXIT.

有人可以用我的约束语法帮助我吗？

Answer 1

主键约束的声明中存在语法错误。主键约束不是检查约束，因此您不需要CHECK关键字。每个内联约束定义

后还需要逗号

SQL> ed
Wrote file afiedt.buf

  1     CREATE TABLE  Students
  2  (
  3  id                INTEGER,
  4  name              CHAR(10)    NOT NULL,
  5  classification    CHAR(10)    NOT NULL,
  6  hours             INTEGER,
  7  gpa               NUMBER(3,2) NOT NULL,
  8  mentor            INTEGER,
  9  CONSTRAINT IC1 PRIMARY KEY (id),
 10  CONSTRAINT IC2 CHECK (classification = 'freshman' or classification = 'sophomore' or classification = 'junior' or classification = 'senior'),
 11  CONSTRAINT IC3 CHECK (gpa >= 0 AND gpa <= 4) ,
 12* CONSTRAINT IC4 CHECK (classification = 'junior' AND hours >= 55 AND hours <= 84)  )
SQL> /

Table created.

根据您使用的前端工具和该工具的设置，您可能希望避免在SQL语句中间出现完全空行。从SQL的角度来看，这是完全有效的语法。但是一些前端会将空行解释为结束先前的陈述。

Oracle中的完整性约束

1 个答案: