7. Features SQL
Server
• Consists of several features. A
few are:
• Query Analyzer
• Profiler
• Service Manager
• Bulk Copy Program (BCP)
8. Profiler
• Monitoring tool
• Used for performance tuning
• Uses traces – an event monitoring protocol
• Event may be a query or a transaction like logins etc
9. Service Manager
• Helps us to manage services
• More than one instance of SQL server can be installed in a machine
• First Instance is called as default instance
• Rest of the instances (16 max) are called as named instances
• Service manager helps in starting or stopping the instances
individually
10. Instances
• Each instance is hidden from another instance
• Enhances security
• Every instance has its own set of Users, Admins, Databases, Collations
• Advantage of having multiple instance is
• Multi company support (Each company can have its own instance and create
databases on the same server, independent on each other)
• Server consolidation (Can host up to 10 server applications on a single
machine)
11. BCP
• Bulk Copy Program
• A powerful command line utility that enables us to transfer large
number of records from a file to database
• Time taken for copying to and from database is very less
• Helps in back up and restoration
12. Query Analyzer
• Allows us to write queries and SQL statements
• Checks syntax of the SQL statement written
• Executes the statements
• Store and reload statements
• Save the results in file
• View reports (either as grid or as a text)
13. SQL Database Objects
• A SQL Server database has lot of objects like
• Tables
• Views
• Stored Procedures
• Functions
• Rules
• Defaults
• Cursors
• Triggers
14. System Databases
• By default SQL server has 4 databases
• Master : System defined stored procedures, login details, configuration
settings etc
• Model : Template for creating a database
• Tempdb : Stores temporary tables. This db is created when the server starts
and dropped when the server shuts down
• Msdb : Has tables that have details with respect to alerts, jobs. Deals with SQL
Server Agent Service
15. Creating a database
• We need to use Master database for creating a database
• By default the size of a database is 1 MB
• A database consists of
• Master Data File (.mdf)
• Primary Log File (.ldf)
16. Database operations
• Changing a database
Use <dbname>
• Creating a database
Create database <dbname>
• Dropping a database
Drop database <dbname>
17. SQL Server Data types
• Integer : Stores whole number
• Float : Stores real numbers
• Text : Stores characters
• Decimal: Stores real numbers
• Money : Stores monetary data. Supports 4 places after decimal
• Date : Stores date and time
• Binary : Stores images and other large objects
• Miscellaneous : Different types special to SQL Server.
(Refer to notes for more info)
19. Select Statements
• To execute a statement in MS SQL, Select the statement and Click on the Execute button in the
query analyser or press F5
• This is used to retrive records from a table
• Eg. Select * from table1;
• This will fetch all rows and all columns from table1
• Eg. Select col1,col2 from table1
• This will fetch col1 and col2 from table1 for all rows
• Eg. Select * from table1 where <<condn>>
• This will fetch all rows from table1 that satisfies a condition
• Eg. Select col1,col2 from table1 where <<condn>>
• This will fetch col1 and col2 of rows from table1 that satisfies a condition
20. Select Options
• Aggregate functions
• Sum(col1): sum of data in the column col1
• Max(col1): data with maximum value in col1
• Min(col1): data with minimum value in col1
• Avg(col1): Average of data in col1
• Count(col1): Number of not null records in table
• Grouping – Group by col1 : Groups data by col1
• Ordering – Order by col1 : Orders the result in ascending order
(default order) of col1
• Filtering – Where <<condn>> and Having <<condn>>
21. Table management
Create table tablename
(
col1 data type,
col2 data type
);
- Creates a table with two columns
Drop table tablename;
- Drops the table structure
22. Insert statements
• Inserting data to all columns
• Insert into tablename(col1,col2) values(v1,v2)
• Insert into tablename values(v1,v2)
• Inserting data to selected columns
• Insert into tablename(col1) values (v1)
• Insert into tablename(col2) values (v2)
23. Update statement
Update table tablename
Set colname=value
- This updates all rows with colname set to value
Update table tablename
Set colname=value
Where <<condition>>
- This updates selected rows with colname as value only if the row
satisfies the condition
24. Delete statements
Delete from table1;
Deletes all rows in table1
Delete from table1 where <<condition>>
Deletes few rows from table1 if they satisfy the condition
25. Truncate statement
• Truncate table tablename
• Removes all rows in a table
• Resets the table.
• Truncate does the following, where as delete statement does not
• Releases the memory used
• Resets the identity value
• Does not invoke delete trigger
26. Alter statements
• Used to modify table structure
• Add new column
• Change data type of existing column
• Delete a column
• Add or remove constraints like foreign key, primary key
27. More table commands
• Viewing tables in a data base:
• Exec sp_tables “a%”
• This gives all tables in the current database that starts with “a”
• Viewing table strucure:
• Exec sp_columns <<tablename>>
• Exec sp_columns student;
28. Joins
• Cross Join
• Cartesian product. Simply merges two tables.
• Inner Join
• Cross join with a condition. Used to find matching records in the two tables
• Outer Join
• Used to find un matched rows in the two tables
• Self Join
• Joining a table with itself
29. Cross Join
There are two tables A and B
A has a column Id and data (1,2,3)
B has a column Id and data (A,B)
If I put
Select A.Id, B.Id from A,B
This generates output as
A 1
B 1
C 1
A 2
B 2
C 2
30. Self Join
There is a table called Emp with the following structure:
empid ename mgrid
1 A null
2 B 1
3 C 1
4 D 2
If I want to print all managers using self join, I should write quey as:
select e1.ename from
emp e1,emp e2
where e1.mgrid = e2.empid
31. Inner Join
I have 2 tables Student(sid,Name) and Marks(Sid,Subject,Score)
If I want to print the marks of all students in the following format,
Name Subject Score
Select Name,Subject,Score from
Student s join Marks m
On s.sid = m.sid
32. Outer Join
• Right outer Join
• Print all the records in the second table with null values for missing records in
the first table
• Left outer Join
• Print all the records in the first table with null values for missing records in the
second table
• Full outer Join
• Prints all records in both the table with null values for missing records in both
the table
33. Left Outer Join
I have a table Employee (Eid, Ename, Mid) and
a table Machine (Mid,ManufacturerName)
Employee
Eid EName Mid
1 ABC 1
2 DEF 3
Machine
Mid ManufacturerName
1 Zenith
2 HP
34. Left Outer Join
I want to print the employee name and machine name.
If I write a query using inner join, then the second employee will
not be displayed as the mid in his record is not avilable with the second
table.
So I go for left outer join. The query is as shown below:
Select Ename, ManufacturerName from Employee e left outer join
Machine m on e.Mid = m.Mid
35. Right outer Join
Assume data in the tables like this:
Employee
Eid EName Mid
1 ABC 1
2 DEF
Machine
Mid ManufacturerName
1 Zenith
2 HP
36. Right Outer Join
If I want to find which machine is unallocated, I can use right outer join.
The query is as follows:
Select Ename, ManufacturerName from Employee e right outer join
Machine m on e.Mid = m.Mid
This yields a result
ABC Zenith
HP
37. Full Outer Join
Assume data in the tables like this:
Employee
Eid EName Mid
1 ABC 1
2 DEF
3 GHI 2
Machine
Mid ManufacturerName
1 Zenith
2 HP
3 Compaq
38. Full Outer Join
If I want to find people who have been un allocated with a system and
machines that are been un allocated, I can go for full outer join.
Query is like this:
Select Ename, ManufacturerName from Employee e full outer join
Machine m on e.Mid = m.Mid
This yields a result
ABC Zenith
DEF
GHI HP
Compaq
39. Views
• Views are logical tables
• They are pre compiled objects
• We can select few columns or rows from a table and put the data set
in a view and can use view in the same way as we use tables
40. Views
• Create views:
Create view viewname as select stmt
Create view view_emp as select empid,
empname from employee;
• Select from views:
Select * from viewname
Select empid,empname view_emp;
• Drop views:
Drop view viewname
Drop view view_emp;
41. String Functions
• Substring(string,start,length) – Will fetch characters starting at a
specific index extending to length specified.
• Left(string,length) – Fetches number of characters specified by length
from left of the string
• Right(string,length) – Fetches number of characters specified by
length from right of the string
• Len(string) – Returns the length of a string
42. String Functions
• Ltrim(string) – Removes leading spaces in a string
• Rtrim(string) – Removes trailing spaces in a string
• Lower(string) – Converts the characters in a string to lower case
• Upper(string) – Converts the characters in a string to upper case
43. Numeric Functions
• ABS(Number) – Fetches the modulo value (Positive value) of a
number
• CEILING(Number) – Fetches the closest integer greater than the
number
• FLOOR(Number) – Fetches the closest integer smaller than the
number
• EXP(Number) – Fetches the exponent of a number
44. Numeric Functions
• POWER(x,y) – Fetches x raised to the power of y
• LOG(Number) – Fetches the natural logarithmic value of the number
• LOG10(Number) – Fetches log to the base 10 of a number
• SQRT(Number) – Fetches the square root of a number
45. Indexes
• Indexes make search and retrieve fast in a database
• This is for optimizing the select statement
• Types of index
• Unique
• Non unique
• Clustered
• Non clustered
46. Index
Create index indexname on
tablename(columnname)
This creates a non clustered index on a table
Create unique clustered index index_name on
Student(sname);
This creates a unique and clustered index on the
Column Sname.
47. Sequences
• This creates an auto increment for a column
• If a table has a column with sequence or auto increment, the user
need not insert data explicitly for the column
• Sequence is implemented using the concept of Identity
48. Identity
• Identity has
• A seed
• An increment
• Seed is the initial value
• Increment is the value by which we need to skip to fetch the
nextvalue
• Identity(1,2) will generate sequence numbers 1,3,5,7…
49. Sample
Create table table1
(
Id integer identity(1,1),
Name varchar(10)
)
It is enough if we insert like this:
Insert into table1(name) values(‘Ram’);
Ram will automatically assigned value 1 for id
