2. Database Server
Operates as a separate “process”
Need to communicate with the server using a separate
application
Connection required to transmit request and response
Management Studio and SQL Server are different
programs
3. Managing SQL Server
Management Studio gives access to most
functions/operations
Query window provides method to write/execute T-
SQL statements
“T” = transact
SQL Service Manager provides way to start/stop Server
4. SQL Server Databases
Two files are maintained
Data file (.mdf)
Transaction Log file (.ldf)
Files can be spread over multiple machines
Always need a primary file group
5. Database Contents
Tables
User tables hold data
System tables hold data about the database
Stored Procedures, User Defined Functions
Views
Indexes
6. Default Databases
Master: Logins/User roles; system configuration;
names/locations of databases; SQL Server startup
Tempdb: Lasts duration of SQL Server session;
temporary holding space
Model: Sets characteristics of new databases
MSDB: Holds information about jobs SQL Server
Agent runs
7. Security
Windows Authentication: Windows network logins
used
Mixed-mode: Windows OR SQL Server logins used
Login: To access server
User: To access a database
Network security trumps all….
8. Roles
Server – administrative functions
Task based:
Backup
Create database
Roles are fixed
Database/Application – groups of users with common
activities
Read/write all data
Read/write select data
Read data only
9. Normalization
Process for reducing duplicate and redundant data
1st Normal Form: eliminate repeating groups
2nd Normal Form: each column in a table depends on
the primary key
can’t get information with only part of the key
3rd Normal Form: A column cannot be dependent on
another column that isn’t the primary key
10. Relationships
Types
One-to-one
One-to-many
Many-to-many
Requires a primary key on the ‘one’ side, foreign key on
the ‘many’ side
Referential Integrity defines how values work across
tables
11. Table Definition
Fields need a name and datatype
SQL Server datatypes are different from Access and
procedural programming language datatypes
Fieldnames can include spaces – but poor practice
Identity – create unique number for each row
12. Constraints
Allow Null – value not required to add record
Check Constraints – test field or row values
Default value – if no data is entered into a field
Unique – values must be different for each row
13. Database Diagrams
Illustrate database design
Add, modify tables, indexes, relationships
Can control view, table details
14. Indexes
Help to select and find records
Serve as a “cross-reference”
Can be based on one or more fields
15. Good Index Characteristics
Low maintenance columns
Includes columns used frequently in Where or Order
By clauses
Don’t have to go out to table for data
Help search for ranges of records
16. Action Queries
Insert: insert into tablename(fieldlist) values(valuelist)
Update: update tablename set
field1=value1, field2=value2
Delete: delete from tablename [where condition]
17. Select Statement
Can use an alias for fields and/or tables
Select fields
From table
Join table On field=field
Inner – both tables have records with matching values
Outer – all records from one table and any matches found in
second table
18. Where
Conditions to determine records returned
Multiple conditions require And … Or
Can use where clause to implement join between
tables
Sub-queries allow tables to be limited by values in a
second table without using a join
20. View Performance
By default views run just as a query processed from
command line
Adds second step to execution:
select from view
execute view itself
Can add an index to speed execution
Specific requirements when creating an index on a view
21. Declaring & Using Variables
Use Declare
Must use Set or Select to assign
Variables are local to a procedure
22. System Variables
@@ identifies system variables
Value of a system variable can change
@@Rowcount changes with next select, update, insert or
delete
@@Error changes with each instruction
@@Identity changes with next insert
23. Decision-making
IF … ELSE
No end if
Need to use Begin/End if have more than one
instruction to execute
IF StartDate < EndDate
Begin
…
End
ELSE
24. Simple Case Statement
CASE
Similar to SELECT CASE
Compares one value to different cases
CASE Category
WHEN ‘pop_comp’ THEN ‘Popular Computing’
WHEN ‘mod_cook’ THEN ‘Modern Cooking’
END
25. Searched Case
No test expression
Each WHEN has a boolean test
CASE
WHEN Points >= 90 THEN ‘A’
WHEN Points < 90 AND Extra > 0
THEN ‘A’
END
26. Errors
Errors can occur because of SQL statement
Invalid syntax, or data type
Errors can also reflect business rules
Data doesn’t match requirements
27. Try/Catch
Similar to .Net languages
Need to include BEGIN/END
BEGIN TRY
<code>
END TRY
BEGIN CATCH
<error handling code>
END CATCH
28. BATCH
Batch is a logical group of SQL statements
Run-time error will halt execution only of FURTHER
steps
Can break up multiple steps using GO
Not available in all tools
GO causes editing tool to send statements to that point
for execution
GO isn’t sent to SQL Server
29. Stored Procedures
“Code” written in Structured Query Language
Different from a Script
Script is a text file that is run
Sproc is compiled and stored in the database
30. Using Stored Procedures
Use Execute to call
Procedures generate a return value
Return value is about success of execution
Exec spName(parameters) doesn’t capture the return
value
Exec @Variable = spName(parameters) captures return
value
31. Parameters
Can use any SQL data type or User Defined Data Types
Input: Values sent into the stored procedure
Required unless there’s a default value
Output: Values sent to the calling routine
Output parameter is different than return value!
Must be specified as output; default is an input
parameter
32. Writing Stored Procedures
Make modular
Use RaisError to send a message
Message can be a string or refer to a message number
User-defined messages start at 50001 and are stored on
server – not in database!
33. User-defined Functions
Similar to stored procedures, but
Aren’t executed (no EXEC)
Can be run “in-line” (as part of another SQL statement)
Return a value (scalar) or table, don’t have a “return
value” or output parameters
34. Triggers
Typically used to enforce rules, log activity, or maintain
data (archive)
Similar to a stored procedure
Respond to actions on a table
Trigger is not called
Trigger is specific to a table
Table can have multiple triggers
One trigger can respond to different actions
35. Triggers & Constraints
Constraints give better performance
Triggers can span tables, databases, servers;
constraints are table specific
If testing a value inserted in one table depends on an
entry in another table, use a trigger
If testing a value depends on an entry in the current
row, a relationship, or function result, use a constraint
36. Types of Triggers
FOR/AFTER execute after data has been written to
tables
Constraints have already been satisfied
INSTEAD OF executes before changes are written
Trigger must complete requested action if appropriate
37. Update()
Can test if a column has changed
Update(columnname)
If Update(FirstName)
Print ‘FirstName has changed’
38. Transactions
Provides method for canceling an operation
Can restore rows, columns to original state in event of
error or business logic failure
Use when changes will either be committed or
discarded in entirety
Begin Tran: Identifies the start
Commit Tran: Write changes
Rollback Tran: Cancel changes
39. ACID
Atomicity: All of the changes will be accepted or none
of the changes will be accepted
Consistency: Data is either in its original or changed
state
Isolation: If multiple transactions occur, data is never
available in an intermediate state
Durability: Once finished, all changes are complete
and changes can only be done by another
transaction/unit of work
40. Locking & Concurrency
Locking prevents other operations from changing that
data
Concurrency refers to multiple actions running against
database at the same time
What happens if you want to change data I’m working
with?
