A collection of basic SQL Syntax (i)--data definition

Defining a basic table *********************************************

Create a "student" table student

CREATE TABLE Student

(Sno CHAR (9) PRIMARY KEY,

Sname CHAR (a) UNIQUE,

Ssex CHAR (2),

Sage SMALLINT,

Sdept CHAR (20)

);

Create a "curriculum" Course

CREATE TABLE Course

(Cno CHAR (4) PRIMARY KEY,

Cname CHAR (40),

Cpno CHAR (4),

Ccredit SMALLINT,

foreing KEY cpno REFERENCES Course (Cno)

)

Set up Student Timetable SC

CREATE TABLE SC

(Sno CHAR (9),

Cno CHAR (4),

Grade SMALLINT,

PRIMARY KEY (Sno, Cno),

Foreing KEY (Sno) REFERENCES Student (Sno),

Foreing KEY (Cno) REFERENCES Course (Cno),

);

Modify the base table *********************************************

Add the Entry Time column to the student table whose data class type is date

ALTER TABLE Student ADD s_enrrance DATE;

Change the age data type from character type to integer type

Alter TABLE Student ALTER COLUNM Sage INT;

Adding a course name must be a unique and worthy constraint

ALTER TABLE Course ADD UNIQUE (Cname);

Delete base table *********************************************

Delete Student Table

DROP TABLE Student CASCADE;

A collection of basic SQL Syntax (i)--data definition