DBMS | Practicals

No SQL DESCRIPTION
1 SELECT DATA RETRIEVAL
2 INSERT
UPDATE
DELETE
DATA MANIPULATION LANGUAGE (DML)
3 CREATE
ALTER
DROP
RENAME
TRANCATE
DATA DEFINATION LANGUAGE (DDL)
4 COMMIT
ROLLBACK
SAVEPOINT
RENAME
TRANCATE
TRANSICTION CONTROL LANGUAGE (TCL)
5 GRAND
REVOKE
DATA CONTROL LANGUAGE (DCL)
No LABs PRACTICALS
1 LAB-1 CREATE TABLE
Syntax:
CREATE TABLE schema_name.table_name (
column_1 data_type column_constraint,
column_2 data_type column_constraint,
...
table_constraint
);
Example:
create table DEPARTMENT (
deptno number,
deptname varchar2(50) not null,
location varchar2(50),
constraint pk_department primary key (deptno)
);

create table EMPLOYEE (
empno number,
name varchar2(50) not null,
jobtitle varchar2(50),
manager number,
hiredate date,
salary number(7,2),
commission number(7,2),
deptno number,
constraint pk_employee primary key (empno),
constraint fk_employee_deptno foreign key (deptno)
references DEPARTMENT (deptno)
);
2 LAB-2 ALTER TABLE
It is used to add, MODIFY, or drop columns.

Syntax for ADD:

ALTER TABLE table_name ADD (column datatype,column datatype....);
Example:
Suppose we want to ADD new column (location) in existing table
ALTER TABLE department ADD location varchar2(50);

Syntax for MODIFY:

ALTER TABLE table_name MODIFY (column datatype,column datatype....);
Example:
Suppose we wants to change/modify the size of column location from 50 to 20
ALTER TABLE deptartment MODIFY location varchar(20);

Syntax for DROP:

ALTER TABLE table_name DROP COLUMN column_name ;
Example:
Suppose we wants to remove the column location from department table.
ALTER TABLE dept DROP COLUMN location

Syntax for RENAME COLUMN NAME:

ALTER TABLE table_name RENAME COLUMN old_column_name TO new_column_name ;
Example:
Suppose we wants to rename/ change the name of column.
ALTER TABLE dept RENAME COLUMN location to dept_loc

Syntax for RENAME table NAME:

RENAME table_name TO new_table_name;
Example:
Suppose we wants to rename/ change the name of TABLE.
RENAME dept TO department;
3 LAB-3 DROP TABLE
Dorp command will drop/remove the structure of table
Syntax: DROP TABLE table_name;
Example: DROP TABLE department;
4 LAB-4 TRUNCATE
We can not ROLLBACK trancated table.It is parmanent deleted from storage.
Syntax: TRUNCATE table table_name;
Example: TRUNCATE table emp;
5 LAB-5 Working with Constraints
Following Constraints are used in SQL
Type of COnstraints:
  • NOT NULL
  • UNIQUE
  • PRIMARY KEY
  • FOREIGN KEY
  • CHECK
Examples: Different Way to define Constraints

1. CREATE TABLE EMPLOYEE(
EID NUMBER(6) PRIMARY KEY,
ENAME VARCHAR2(50) NOT NULL,
SAL NUMBER(9) CHECK(SAL<>>0),
AGE NUMBER(2) CHECK(AGE>18)
)

2. CREATE TABLE EMPLOYEE(
EID NUMBER(6) CONSTRAINT EMP_EID PRIMARY KEY,
ENAME VARCHAR2(50) CONSTRAINT EMP_ENAME NOT NULL,
SAL NUMBER(9) CONSTRAINT EMP_SAL CHECK(SAL<>0),
AGE NUMBER(2) CONSTRAINT EMP_AGE CHECK(AGE>18)
)

3. CREATE TABLE EMPLOYEE(
EID NUMBER(6),
ENAME VARCHAR2(50) NOT NULL,
SAL NUMBER(9),
AGE NUMBER(2),
CONSTRAINT EMP_EID_PK PRIMARY KEY (EID),
CONSTRAINT EMP_SAL_CK CHECK(SAL<>0),
CONSTRAINT EMP_AGE_CK CHECK(AGE>18)

)

4. DEFINE FOREIGN KEY CONTRAINT
CREATE TABLE DEPARTMENT(
DID NUMBER(6) PRIMARY KEY,
DNAME VARCHAR2(50) NOT NULL
)
CREATE TABLE EMPLOYEE(
EID NUMBER(6) PRIMARY KEY,
ENAME VARCHAR2(50) NOT NULL,
DID NUMBER(6) REFERENCES DEPARTMRNT(DID)
)

OR

CREATE TABLE DEPARTMENT(
DID NUMBER(6) PRIMARY KEY,
DNAME VARCHAR2(50) NOT NULL
)
CREATE TABLE EMPLOYEE(
EID NUMBER(6) PRIMARY KEY,
ENAME VARCHAR2(50) NOT NULL,
DID NUMBER(6) CONSTRAINT DID_FK REFERENCES DEPARTMRNT(DID)
)

OR

CREATE TABLE DEPARTMENT(
DID NUMBER(6) PRIMARY KEY,
DNAME VARCHAR2(50) NOT NULL
)
CREATE TABLE EMPLOYEE(
EID NUMBER(6) PRIMARY KEY,
ENAME VARCHAR2(50) NOT NULL,
DID NUMBER(6),
CONSTRAINT EMP_DID_FK FOREIGN KEY (DID) REFERENCES DEPARTMRNT(DID)
)
4 LAB-4 RENAME
INFO
Syntax:
Example:

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