SQL Basic 1
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Transcript of SQL Basic 1
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Experiment No. – 9, 10
Aim: To Study SQL Basics.
Teory:
SQL is a standard language for accessing and manipulating databases.
• SQL stands for Structured Query Language
• SQL lets you access and manipulate databases
• SQL is an ANSI (American National Standards Institute) standard
What Can SQL do?
• SQL can execute queries against a database
• SQL can retrieve data from a database
• SQL can insert records in a database
• SQL can update records in a database
• SQL can delete records from a database
• SQL can create ne databases
• SQL can create ne tables in a database
• SQL can create stored procedures in a database
• SQL can create vies in a database
• SQL can set permissions on tables! procedures! and vies
RDBMS
"#$%S stands for "elational #atabase %anagement System.
"#$%S is t&e basis for SQL! and for all modern database systems suc& as %S SQL Server! I$% #$'!
racle! %ySQL! and %icrosoft Access.&e data in "#$%S is stored in database ob*ects called tables.
A table is a collection of related data entries and it consists of columns and ros.
SQL DML and DDL
SQL can be divided into to parts+ &e #ata %anipulation Language (#%L) and t&e #ata #efinition
Language (##L).
&e query and update commands form t&e #%L part of SQL+
• SELE!T , extracts data from a database
• "#$ATE , updates data in a database
• $ELETE , deletes data from a database
• %NSE&T %NT' , inserts ne data into a database
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&e ##L part of SQL permits database tables to be created or deleted. It also defines indexes (-eys)!
specifies lin-s beteen tables! and imposes constraints beteen tables. &e most important ##L
statements in SQL are+
• !&EATE $ATABASE , creates a ne database
• ALTE& $ATABASE , modifies a database
• !&EATE TABLE , creates a ne table
• ALTE& TABLE , modifies a table
•
$&'# TABLE , deletes a table• !&EATE %N$E( , creates an index (searc& -ey)
• $&'# %N$E( , deletes an index
1. The CREATE TABLE Statement
&e "/A/ A$L/ statement is used to create a table in a database.
SQL CREATE TABLE Syntax
"/A/ A$L/ table0name
(
column0name1 data0type!
column0name' data0type!
column0name2 data0type!
....
)
&e data type specifies &at type of data t&e column can &old.
SQL) !&EATE TABLE Students * +%$ int,
Name -arcar+100,
/ Branc -arcar+100,
Ae int2
Ta34e created.
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2.The SQL SELECT Statement
&e S/L/ statement is used to select data from a database.
&e result is stored in a result table! called t&e result,set.
SQL SELECT Syntax
S/L/ column0name(s)
3"% table0name
and
S/L/ 4 3"% table0name
SQL> select !"om st#dents$
no "o%s selected
&&&&&&&&&&& &&&&&&&&&& &&&&&&&&&&&&&
'.The ()SERT ()T* Statement
&e INS/" IN statement is used to insert a ne ro in a table.
SQL ()SERT ()T* Syntax
It is possible to rite t&e INS/" IN statement in to forms.
&e first form doesn5t specify t&e column names &ere t&e data ill be inserted! only t&eir values+
INS/" IN table0name
6AL7/S (value1! value'! value2!...)
&e second form specifies bot& t&e column names and t&e values to be inserted+
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INS/" IN table0name (column1! column'! column2!...)
6AL7/S (value1! value'! value2!...)
SQL) insert into students
* -a4ues+1,5sana5,5computer5,02
1 ro6 created.
SQL) insert into students+%$,Name,Branc,Ae
* -a4ues+*,5seema5,5%T5,02
1 ro6 created.
SQL) se4ect 7 8rom Students2
%$ NAE B&AN! A;E
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SQL) se4ect distinct Branc 8rom students2
B&AN!
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* 6ere id?1 or Ae?*>2
NAE
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Note: Notice t&e 89/"/ clause in t&e 7
SQL) update students
* set 3ranc?5ec5
6ere name?5=on52
1 ro6 updated.
SQL) se4ect 7 8rom students2
%$ NAE B&AN! A;E
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