Database Management System Lecture - 26 © Virtual University of Pakistan

© Virtual University of Pakistan DDL Create Alter Drop © Virtual University of Pakistan

© Virtual University of Pakistan Create Command Creating database CREATE DATABASE db_name Create database exam Next step is to create tables Two approaches: Through SQL Create command Through Enterprise Manager © Virtual University of Pakistan

© Virtual University of Pakistan Create Table Command Create table command is used to: Create a table Define attributes of the table with data types Define different constraints on attributes, like primary and foreign keys, check constraint, not null, default value etc. © Virtual University of Pakistan

© Virtual University of Pakistan Format of Create Table CREATE TABLE     [ database_name.[ owner ] . | owner. ] table_name     ( { < column_definition >         | column_name AS computed_column_expression         | < table_constraint > }   | [ { PRIMARY KEY | UNIQUE } [ ,...n ] ]     ) © Virtual University of Pakistan

© Virtual University of Pakistan Chevrons Explained < column_definition > ::= { column_name data_type }       [ DEFAULT constant_expression ]       [ < column_constraint > ] [ ...n ] © Virtual University of Pakistan

© Virtual University of Pakistan Chevrons Explained < column_constraint > ::= [ CONSTRAINT constraint_name ]     { [ NULL | NOT NULL ]         | [ { PRIMARY KEY | UNIQUE }           ]         | [ [ FOREIGN KEY ]             REFERENCES ref_table [ ( ref_column ) ]             [ ON DELETE { CASCADE | NO ACTION } ]             [ ON UPDATE { CASCADE | NO ACTION } ]           ]         | CHECK( logical_expression )     } © Virtual University of Pakistan

© Virtual University of Pakistan Create Table Command CREATE TABLE Program ( prName char(4), totSem tinyint, prCredits smallint) © Virtual University of Pakistan

© Virtual University of Pakistan Create Table Command CREATE TABLE Student (stId char(5), stName char(25), stFName char(25), stAdres text, stPhone char(10), prName char(4) curSem smallint, cgpa real) © Virtual University of Pakistan

Create Table with Constraint CREATE TABLE Student ( stId char(5) constraint ST_PK primary key constraint ST_CK check (stId like ‘S[0-9][0-9][0-9][0-9]'), stName char(25) not null, stFName char(25), stAdres text, stPhone char(10), prName char(4), curSem smallint default 1, cgpa real) © Virtual University of Pakistan

© Virtual University of Pakistan stId char(5) constraint ST_PK primary key stId char(5) primary key © Virtual University of Pakistan

Create Table with Constraint CREATE TABLE Student (stId char(5) primary key check (stId like 'S[0-9][0-9][0-9][0-9]'), stName char(25) not null, stFName char(25), stAdres text, stPhone char(10), prName char(4), curSem tinyint default 1, cgpa real) © Virtual University of Pakistan

Create Table with Constraint CREATE TABLE semester ( semName char(5) primary key, stDate smalldatetime, endDate smalldatetime, constraint ck_date_val check (datediff(week, stDate, endDate) between 14 and 19)) © Virtual University of Pakistan

Database Management System Lecture - 26 © Virtual University of Pakistan