Sql xp 06

Manage Data in Tables

Objectives
In this lesson, you will learn to:
Create rules
Create defaults
Maintain data in a table by using
INSERT statement
UPDATE statement
DELETE statement
Truncate a table

©NIIT SQL/Lesson 6/Slide 1 of 50


6.D.1 Creating a Rule
The zip code in the Newspaper table should be of the
character type and should have the following pattern:
[0-9][0-9][0-9][0-9][0-9]-[0-9][0-9][0-9][0-9]
An example of such a pattern is: 42482-4353
Without changing the table structure, how can you ensure
that you can meet this requirement?



Task List
Identify how to implement the constraint without changing
the table structure
Draft the statement to create a rule
Create the rule
Bind the rule to the column
Verify the constraint by inserting data in the table



Identify how to implement the constraint without
changing the table structure
A rule provides a mechanism for enforcing domain integrity
for columns or user-defined datatypes. The rule is applied to
the column or the user-defined datatype before an INSERT
or UPDATE statement is issued.
Result:
The constraint can be implemented by using rules.



Draft the statement to create a rule
The CREATE RULE Statement: Is used to create a rule
Syntax
CREATE RULE rule_name
AS conditional_expression
Action:
The rule would be applied on the cNewspaperCode
attribute
The condition to be applied is:
@ZipCode LIKE '[0-9][0-9][0-9][0-9][0-9]-
[0-9][0-9][0-9][0-9]'
The name of the rule would be rulZipCode



Draft the statement to create a rule (Contd.)
The rule can be created as follows:
CREATE RULE rulZipCode
AS
@ZipCode LIKE '[0-9][0-9][0-9][0-9][0-9]-
[0-9][0-9][0-9][0-9]'



Create the rule
Action:
In the Query Analyzer window, type the query
Press F5 to execute the query



Bind the rule to the column
Binding Rules
A rule can be bound using the sp_bindrule system
store procedure
Syntax
sp_bindrule rule_name, object_name
[,FUTUREONLY]
Unbinding Rules
A rule can be unbound from a column or user-defined
datatype using the sp_unbindrule system stored procedure
Syntax
sp_unbindrule object_name [, FUTUREONLY]



Bind the rule to the column (Contd.)
Action:
In the Query Analyzer, type:
sp_bindrule rulZipCode,'Newspaper.cZip'
Press F5 to execute the code



Verify the constraint by inserting data in the table

Action

Test case cZip to be Result
inserted
1 3452345 The row would not be inserted, as
the zip code is not in the valid
format
2 34563-5678 The row would be inserted, as the
zip code is in the valid format



Just a Minute…
Which system stored procedure is used to bind and unbind a
rule?



6.D.2 Creating a Default
The data entry operator complains that for most rows, he
has to repeatedly enter the code 001 for the cCountryCode
attribute of the Newspaper table. You need to simplify the
data entry task without modifying the table structure.



Task List
Identify how the data entry task can be simplified
Draft the statement to create a default
Create the default
Bind the default to the column
Verify the default by adding a row with the DEFAULT value



Identify how the data entry task can be simplified
Default
It is a constant value assigned to a column, into which the
user need not insert values
Result:
The data entry task can be simplified by using defaults



Draft the statement to create a default
The CREATE DEFAULT Statement
Syntax
CREATE DEFAULT default_name
AS constant_expression
Action:
The default would be applied on the Newspaper table
The column on which the default would be applied is
cCountryCode
The default value is '001’



Draft the statement to create a default (Contd.)
The code for creating the default can be written as
CREATE DEFAULT defCountry
AS '001'



Create the default
Action:
In the Query Analyzer window, type the query



Bind the default to a column
Binding Defaults - After a DEFAULT is created, it needs to
be bound to a column or a user-defined datatype
Syntax
sp_bindefault default_name, object_name [,
FUTUREONLY]
Unbinding Defaults - Defaults can be unbound from a
column or user-defined datatype using the sp_unbindefault
system stored procedure
Syntax
sp_unbindefault object_name [, FUTUREONLY]



Bind the default to a column (Contd.)
Action:
sp_bindefault
defCountry,'Newspaper.cCountryCode'



Verify the default by adding a row with the DEFAULT
value
Action:
INSERT INTO Newspaper
VALUES('0008','Kansas
Today','Kansas','Genral','Robin
Paul','1925 Shawnee Dr ','Kansas
City','Kansas','66106-3025',DEFAULT,'(913)
362-9529','(913)362-9515')
Press F5 to execute



Maintaining Databases
Data Manipulation Language - Data manipulation involves
inserting, modifying, and deleting data. The Data
Manipulation Language (DML) of Transact–SQL is used to
manipulate data
The three operations that you will typically perform to
maintain a database are:
Insert Rows
Update Rows
Delete Rows



6.D.3 Storing Details in a Table
Recruitment of candidates is done through recruitment
agencies. One of the new recruitment agencies is called
‘Head Hunters’. The details of the Head Hunters are:
Attributes Data
Agency Code 0010
Name Head Hunters
Address 223 Hill Street
City Cleveland
State Ohio
Zip 44167-5943
Phone (440)345-8872
Fax (440)345-8943
Charge 7
Total Paid 1000
The above details are required to be stored in the
RecruitmentAgencies table



Task List
Decide in which table the information is to be added
Identify the values to be inserted
Insert rows into the table
Query the table to verify that data has been inserted



Decide in which table the information is to be added
Result:
The information is to be added in the
RecruitmentAgencies table



Identify the values to be inserted
Result:
In the RecruitmentAgencies table, the values to be inserted
are:
cAgencyCode = '0010'
cName = ‘Head Hunters ',
vAddress = ‘223 Hill Street ',
cCity = 'Cleveland',
cState = ‘Ohio’
cZip = '44167-5943',
cPhone = '(440)345-8872',
cFax = '(440)345-8943',
siPercentageCharge = 7,
mTotalPaid = 1000



Insert rows into the table
The INSERT Statement
You must add data to the database to maintain the latest
information about the organization and the transactions
performed by it. This is done using the INSERT statement
Syntax
INSERT [INTO]{table_name}[(column_list)]
VALUES {DEFAULT values_list|select_statement}



Insert rows into the table (Contd.)
Action:
In the Query Analyzer Window, type:
INSERT INTO RecruitmentAgencies
VALUES('0010','Head Hunters','223 Hill
Street','Cleveland', 'Ohio','44167-
5943','(440)345-8872','(440)345-
8943',7,1000)



Query the table to verify that data has been
inserted
Action:
In the Query Analyzer window, type:
SELECT * FROM RecruitmentAgencies



6.D.4 Storing Data From an Existing Table Into a new
Table
Data for the external candidates with a rating of eight or
above from the ExternalCandidate table is to be copied into
a new table called PreferredCandidate. (The
PreferredCandidate table does not exist).
After the PreferredCandidate table has been created with the
required values, it needs to be updated by adding rows of
external candidates with a rating of seven.



Task List
Identify rows to be inserted
Create the new table with the selected values
Add more rows to the table that has been created
Query the table to check if the rows have been added



Identify rows to be inserted
Result:
The rows to be inserted are of those candidates with a
rating of eight or above from the ExternalCandidate table



Create the new table with the selected values
The SELECT INTO Statement is used to copy contents of one
table into another table
Syntax
SELECT columns_list
INTO new_table_name
FROM table_names
WHERE conditions
Action:
SELECT * INTO PreferredCandidate
FROM ExternalCandidate
WHERE cRating = 8


Add more rows to the table that has been created
The INSERT INTO Statement is used to add data from one
table to another
Syntax
INSERT [INTO] table_name1
SELECT column_name(s)
FROM table_name2
[WHERE condition]
Action:
INSERT INTO PreferredCandidate
SELECT * FROM ExternalCandidate
WHERE cRating = 7


Query the table to check if the rows have been added
Action:
SELECT * FROM PreferredCandidate



Just a Minute…
Which statements allow you to copy contents of one table
into another table?



6.D.5 Updating a Table
The test score of Jane Schaffer who is an external candidate
(cCandidateCode 000049) is to be increased by 2 marks,
due to an error detected in the test correction process.



Task List
Identify attributes that have to be updated
Identify values to be updated
Update rows
Query tables



Identify attributes that have to be updated
Result:
In the ExternalCandidate table, the siTestScore attribute
has to be updated



Identify values to be updated
Result:
The test score of Jane Schaffer who is an external
candidate is to be increased by 2 marks. The
cCandidateCode of Jane is 000049



Update rows
The UPDATE Statement is used to modify data in a database
Syntax
UPDATE table_name
SET column_name = value[,column_name = value]
[FROM table_name]
[WHERE condition]
Action:
UPDATE ExternalCandidate
SET siTestScore=siTestScore+2
WHERE cCandidateCode='000049'



Query Tables
Action:
SELECT * from ExternalCandidate
WHERE cCandidateCode = '000049'



6.D.6 Deleting Data
The ExternalCandidate table contains data on all external
candidates who were rejected after the entrance test. Some
of the data in this table present now is more than two years
old. It is occupying hard disk space that can be used for
some other purpose. This data is not required anymore. You
are required to ensure that this old data is removed from the
ExternalCandidate table.



Task List
Identify rows that need to be deleted
Delete the row(s)
Query the table



Identify rows that need to be deleted
Result:
The rows containing data about the candidates who took
the entrance test more than two years ago



Delete the row(s)
The DELETE Statement is used to delete a row from a table
Syntax
DELETE [FROM] table_name
[ FROM table(s)]
[WHERE condition]
Action:
DELETE FROM ExternalCandidate
WHERE dTestDate dateadd(yy,-2,getdate())



Query the table
Action:
SELECT * FROM ExternalCandidate
WHERE dTestDate dateadd(yy,-2,getdate())
Press F5 to execute



Just a Minute…
Which statement allows the modification of data in a
database?



Truncating a Table
The TRUNCATE TABLE statement
Is used to remove rows from a table
Is identical (functionally) to the DELETE statement
Is faster than DELETE statement
Does not fire a trigger
® Syntax

TRUNCATE TABLE table_name



Summary
In this lesson, you learned that:
Rules and defaults are objects that are bound to columns or
user-defined datatypes for specifying the restricted values
and default values respectively
A rule is created using the CREATE RULE statement, and
bound to the column and user-defined datatypes using the
sp_bindrule procedure
A rule is unbound using the sp_unbindrule procedure
A default is created using the CREATE DEFAULT statement,
and bound to the column and user-defined datatypes using
the sp_bindefault procedure



Summary (Contd.)
A default is unbound using the sp_unbindefault procedure
Data is modified in the database to keep the data up-to-date
The INSERT statement is used to insert rows into tables
You can copy contents of one table into another table by
using the SELECT INTO command
SQL Server provides a row update statement called
UPDATE to modify values within tables
You can delete a row from a table by using the DELETE
statement
You use the TRUNCATE TABLE statement to remove all the
rows from a table

Sql xp 06

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