Download Document

DATA
DATABASE
DATABASE MANAGEMENT SYSTEM
SQL (Structured Query Language)
Datatype
''
' '
Storage Required VARCHAR(4) Storage Required
''
4 bytes
1 byte
'ab'
'ab '
4 bytes
'ab'
3 bytes
'abcd'
'abcd'
4 bytes
'abcd'
5 bytes
'abcdefgh' 'abcd'
4 bytes
'abcd'
5 bytes
Value
CHAR(4)
SQL (Structured Query Language)
Structured Query Language, is a database computer language designed for managing
data in relational database management systems (RDBMS)
SQL is a DSL (Data Sub Language), which is really a combination of two languages.
o Data Definition Language (DDL)
o Data Manipulation Language (DML)
1.
Working with SQL commands like DDL, DML, TCL, DCL
DDL: Data Definition Language
 Create Table
 Alter Table
 Rename
 Truncate
 Drop Table
DML: Data Manipulation Language
 Insert
 Update
 Delete
TCL: Transaction Control Language
 Save Point
 Roll Back
 Commit
DCL: Data Control Language
 Grant
 Revoke
Data Definition Language – Auto commit
Data Manipulation Language - not auto commit
Transaction Control Language
Data Control Language
Data Query Language - Select
DDL COMMANDS
1. COMMAND NAME: CREATE
COMMAND DESCRIPTION: CREATE command is used to create objects in the database.
2. COMMAND NAME: DROP
COMMAND DESCRIPTION: DROP command is used to delete the object from the database.
3. COMMAND NAME: TRUNCATE
COMMAND DESCRIPTION: TRUNCATE command is used to remove all the records from the table
4. COMMAND NAME: ALTER
COMMAND DESCRIPTION: ALTER command is used to alter the structure of database
5. COMMAND NAME: RENAME
COMMAND DESCRIPTION: RENAME command is used to rename the objects.
spool E:\summa\dbfile1.txt
spool off
(object type may be Database or Table)
QUERY: 01
Q1. Write a query to create a table student with reg_no, roll_no, stud_name, batch_no, dept_id, address,
city, pincode.
Syntax for creating a table:
SQL: CREATE <OBJ.TYPE> <OBJ.NAME> (COLUMN NAME.1 <DATATYPE>
(SIZE), COLUMN NAME.1 <DATATYPE> (SIZE) ……………………………);
(object type may be Database or Table)
SQL> create table student(reg_no number(10) primary key,roll_no number(10),stud_name
varchar2(20),batch_no number(10),dept_id char(9),address varchar(40),city
varchar(20),pincode number(6));
Table created.
QUERY: 02
Q2. Write a query to display the column name and datatype of the table student.
Syntax for describe the table:
SQL: DESC <TABLE NAME>;
SQL> desc student;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(10)
ROLL_NO
NUMBER(10)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(40)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
QUERY: 03
Q3. Write a query to create a new table from an existing table with all the fields
Syntax for Create a New Table from an Existing Table with All Fields
SQL> CREATE TABLE <TARGET TABLE NAME> AS SELECT * FROM <SOURCE TABLE
NAME>;
SQL> create table student1 as select * from student;
Table created.
SQL> desc student1;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(10)
ROLL_NO
NUMBER(10)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(40)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
QUERY: 04
Q4. Write a query to create a new table from an existing table with selected fields
Syntax For Create A New Table from An Existing Table With Selected Fields
SQL> CREATE TABLE <TARGET TABLE NAME> AS SELECT COLUMN NAME.1, COLUMN
NAME.2…. FROM <SOURCE TABLE NAME>;
SQL> create table student2 as select reg_no,stud_name from student
Table created.
SQL> desc student2;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(10)
STUD_NAME
VARCHAR2(20)
QUERY: 05
Q5. Write a query to create a new table from an existing table without any record:
Syntax for create a new table from an existing table without any record:
SQL> CREATE TABLE <TRAGET TABLE NAME> AS SELECT * FROM
<SOURCE TABLE NAME> WHERE <FALSE CONDITION>;
SQL> create table student3 as select * from student where 1>2;
Table created.
SQL> desc student3;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(10)
ROLL_NO
NUMBER(10)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(40)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
ALTER & MODIFICATION ON TABLE
QUERY: 06
Q6. Write a Query to Alter the column REG_NO NUMBER (10) TO REG_NO NUMBER (15).
Syntax for Alter & Modify on a Single Column:
SQL > ALTER TABLE <TABLE NAME> MODIFY <COLUMN NAME> <DATATYPE>(SIZE);
SQL> alter table student modify reg_no number(15);
Table altered.
SQL> desc student;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(15)
ROLL_NO
NUMBER(10)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(40)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
QUERY: 07
Q7. Write a Query to Alter the table student with multiple columns
Syntax for alter table with multiple column:
SQL > ALTER TABLE <TABLE NAME> MODIFY (<COLUMN NAME1> <DATATYPE>(SIZE),
<COLUMN NAME2> <DATATYPE> (SIZE)……);
SQL> alter table student modify(roll_no number(7),address varchar2(3));
Table altered.
SQL> desc student;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(15)
ROLL_NO
NUMBER(7)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(3)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
QUERY: 08
Q8. Write a query to add a new column in to student
Syntax for add a new column:
SQL> ALTER TABLE <TABLE NAME> ADD (<COLUMN NAME> <DATA
TYPE> <SIZE>);
SQL> alter table student add(gender char(6));
Table altered.
SQL> desc student;
Name
Null? Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(15)
ROLL_NO
NUMBER(7)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(3)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
GENDER
CHAR(6)
QUERY: 09
Q9. Write a query to add multiple columns in to student
Syntax for add a new column:
SQL> ALTER TABLE <TABLE NAME> ADD (<COLUMN NAME1> <DATA TYPE>
<SIZE>,(<COLUMN NAME2> <DATA TYPE> <SIZE>,…..);
SQL> ALTER TABLE STUDENT ADD(DOB DATE,DOJ DATE);
Table altered.
SQL> DESC STUDENT;
Name
Null?
Type
----------------------------------------- -------- ---------------------------REG_NO
NUMBER(15)
ROLL_NO
NUMBER(7)
STUD_NAME
VARCHAR2(20)
BATCH_NO
NUMBER(10)
DEPT_ID
CHAR(9)
ADDRESS
VARCHAR2(3)
CITY
VARCHAR2(20)
PINCODE
NUMBER(6)
GENDER
CHAR(6)
DOB
DATE
DOJ
DATE
REMOVE / DROP
QUERY: 10
Q10. Write a query to drop a column from an existing table student1.
Syntax for add a new column:
SQL> ALTER TABLE <TABLE NAME> DROP COLUMN <COLUMN NAME>;
SQL> alter table student1 drop column batch_no;
Table altered.
SQL> desc student1
Name
Null?
Type
----------------------------------------- -------- ---------------------------REG_NO
ROLL_NO
STUD_NAME
DEPT_ID
ADDRESS
CITY
NUMBER(10)
NUMBER(10)
VARCHAR2(20)
CHAR(9)
VARCHAR2(40)
VARCHAR2(20)
PINCODE
NUMBER(6)
QUERY: 11
Q11. Write a query to drop multiple columns from student1.
Syntax for add a new column:
SQL> ALTER TABLE <TABLE NAME> DROP <COLUMNNAME1>,<COLUMN
NAME2>,……….. ;
SQL> alter table student1 drop (roll_no,address);
Table altered.
SQL> desc student1;
Name
Null?
Type
----------------------------------------- -------- ---------------------------REG_NO
STUD_NAME
DEPT_ID
CITY
PINCODE
NUMBER(10)
VARCHAR2(20)
CHAR(9)
VARCHAR2(20)
NUMBER(6)
RENAME
QUERY: 12
Q12. Write a query to rename table student1 to studentnew.
Syntax for add a new column:
SQL> ALTER TABLE <OLD NAME> RENAME TO <NEW NAME>
Truncate
Syntax : Truncate table tablename;
Drop Table
Syntax : drop table tablename;
Rename
Syntax : Alter table old table name Rename to new table name
INSERT
Syntax : SQL :> INSERT INTO <TABLE NAME> VALUES< VAL1, ‘VAL2’,…..);
E.g.: SQL>INSERT INTO EMP VALUES(101,'NAGARAJAN','LECTURER',15000);
(OR)
Syntax : SQL :> INSERT INTO <TABLE NAME> VALUES< ‘&column name’, ‘&column
name 2’,…..);
E.g.: SQL> INSERT INTO EMP VALUES(&EMPNO,'&ENAME','&DESIGNATIN','&SALARY');
Select or Display
Syntax : SQL> SELECT * FROM <TABLE NAME>;
E.g.:
SQL> SELECT * FROM EMP;
UPDATE
Q1. Write a query to update the records from employee.
Syntax : SQL> UPDATE <<TABLE NAME> SET <COLUMNANE>=<VALUE> WHERE
<COLUMN NAME=<VALUE>;
E.g.:
SQL> UPDATE EMP SET SALARY=16000 WHERE EMPNO=101;
Syntax for update multiple Records from the table:
SQL> UPDATE <TABLE NAME> SET <COLUMNANE>=<VALUE>,
<COLUMNANE>=<VALUE> WHERE <COLUMN NAME=<VALUE>;
E.g.:
SQL>UPDATE EMP SET SALARY = 16000, DESIGNATIN='ASST. PROF' WHERE
EMPNO=102;
DELETE
Syntax :
SQL> DELETE <TABLE NAME> WHERE <COLUMN NAME>=<VALUE>;
E.g.:
SQL> DELETE EMP WHERE EMPNO=103;
TCL: Transaction Control Language
 Save Point
 Roll Back
 Commit
syntax
savepoint a;
Rollback to a;
Commit;
Eg: for saveponit & rollback
SQL> select * from janani;
REGNO NAME
---------- -------------------101 janani
102 priya
103 qwer
104 tyu
SQL> insert into janani values(105,'rtyu');
1 row created.
SQL> savepoint a;
Savepoint created.
SQL> select * from janani;
REGNO NAME
---------- -------------------101 janani
102 priya
103 qwer
104 tyu
105 rtyu
SQL> rollback to a;
Rollback complete.
SQL> select * from janani;
REGNO NAME
---------- -------------------101 janani
102 priya
103 qwer
104 tyu
Eg: for commit & rollback
SQL> select * from janani;
REGNO NAME
---------- -------------------101 janani
102 priya
103 qwer
104 tyu
SQL> insert into janani values(105,'rtyu');
1 row created.
SQL> select * from janani;
REGNO NAME
---------- -------------------101 janani
102 priya
103 qwer
104 tyu
105 rtyu
SQL> savepoint a;
Savepoint created.
SQL> commit;
Commit complete.
SQL> rollback to a;
rollback to a
*
ERROR at line 1:
ORA-01086: savepoint 'A' never established