1. Database Management System
Lecture - 26
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DDL
Create
Alter
Drop
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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
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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.
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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 ] ]     )
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Chevrons Explained
< column_definition > ::= { column_name data_type }       [ DEFAULT constant_expression ]       [ < column_constraint > ] [ ...n ]
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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 )     }
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Create Table Command
CREATE TABLE Program (
prName char(4),
totSem tinyint,
prCredits smallint)
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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)
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10. 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)
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stId char(5) constraint ST_PK primary key
stId char(5) primary key
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12. 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)
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13. 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))
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14. Database Management System
Lecture - 26
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