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 cant
get information with only part of the key 3rd Normal Form: A column
cannot be dependent on another column that isnt 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 Dont 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 19. Views Pre-defined select statement
Used like a virtual table SELECT * FROM v_CurrentEmployees 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 doesnt match requirements 27. Try/Catch Similar
to .Net languages Need to include BEGIN/END BEGIN TRY END TRY BEGIN
CATCH 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 isnt 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) doesnt 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 theres 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 Arent executed (no EXEC) Can be run in-line
(as part of another SQL statement) Return a value (scalar) or
table, dont 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 Im working with?
