SQL Server

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SQL Server

przygotował: [email protected]
Installation
MS SQL Server
Conditions
1. Every laboratory must be passed and student gets mark for
every laboratory
2. Student must pass finall test, what gives opportunity to get
original Microsoft diploma.
3. Final mark will be an average of marks got during laboratory
and test calculated with the formula:
Final mark = (lab_mark + 2*test_mark)/3
Plan of lecture
1. Installation and configuration of MS SQLServer.
2. Creation and configuration of databases.
3. Users managment.
4. Server administration.
5. Transact SQL.
6. Integration Services.
7. Tuning queries.
8. OLAP.
MS SQL Server
MS SQL Server – relational database with services
enabling management of stored data.
Data models:
OLTP – On-Line Transaction Processing,
OLAP – On-Line Analitycal Processing.
Overview
• SQL Server versions
– First usable: 6.5
– First popular: 7.0
– Other: 2000, 2005
– Current: 2008
MS SQLServer’s tasks
MS SQLServer as database management system:
stores data for transactional and analytical processing,
stores and handles relationships among data,
ensures correctness of data and controls relational rules,
answers client applications requests,
preserves and secures data,
restores data from backups after hardware or software failures.
MS SQL Server
Client
SQL Server
Results
Query
OLTP
OLAP
Client application
Relational Database
System
Client – server architecure
Client components:
1. Client Application
2. Database API – OLE DB, ODBC, JDBC
3. Client Net–Libraries
Server components:
1. Server Net–Libraries
2. Open Data Service
3. Relational Engine
4. Storage Engine
Communication between client
and server
1
Query
Result Set
Database API
(OLE DB, ODBC,
DB-Library)
2
Client
SQL Server
Client Application
Client Net-Library
Server Net-Libraries
3
Open Data Services
Query
5
Result Set
Relational
Engine
Server
4
Storage Engine
Processor
Memory
Local
Database
MS SQL Server components
1. SQL Server Database Engine
2. SQL Server Agent
3. Analysis Services
4. Reporting Services
5. Notification Services
6. Integration Services
SQL Server versions
1. Standard Edition
2. Workgroup Edition
3. Enterprise Edition
4. Developer Edition
5. Microsoft Database Engine (MSDE) (2k)
6. Express Edition (2k5)
7. Mobile Edition
Requirements 2k5 (32(32-bit)
Component
Minimal requirements
Processor
Pentium III, 600 MHz,
better 1 GHz
Memory
Minimum 512 MB
better 1 GB
Hard disk
356 MB
MB
150 MB (database server)
80 MB (client tools)
75 MB (Analysis, Reporting Services)
80 MB (English Query)
Instalation options 2k5
1. x86 – based operating systems
2. x64 – based operating systems
3. Itanium – based operating systems
Installation – parameters
Instance naming:
Default name – computer Windows name
Named instance –format:
<computer name>\<instance name>.
Multiple instances
Instalation parameters
Naming instances - rules:
Shorter than 16 characters case sensitive,
Reserved names Default and MSSQLServer,
Classic rules – no spaces,
First character must be a letter, &, _, or #.
Installation parameters
Authetication modes:
Windows Authentication Mode – SQL Server uses Windows 2000
or NT accounts.
Mixed Mode – SQL Sever uses Windows 2000 or NT accounts
(Windows Authentication) or SQL Server accounts (SQL Server
Authentication)
Other paramaters:
Collation Settings
Server components
SQL Server,
SQL Server Agent,
SQL Server Integration Service,
SQL Server Browser
SQL Server FullText Search
SQL Server Reporting Services
SQL Server Analysis Services
SQL Server VSS Writer
Distributed Transaction Coordinator
Other components
Client Connectivity
Books Online
Business Intelligence Development Studio (2k5)
Code Samples
Database service
1. MS SQL Server: database engine, executes Transact-SQL
queries and manages all files containing database:
a. handles resources for users,
b. coordinates user’s requests,
c.
ensures data consistency.
Some other services
SQL Server Reporting Service
SQL Server Analysis Service
SQL Server Notification Service
...
Verification – services
Running services:
Control Panel/Administration Tools/Services
SQL Service Manager
SQL Server Management Studio
Databases
System Databases
master
model
tempdb
msdb
Adventure
Works
User_1
User_2
User Databases
distribution
Creating database
• The simplest command:
CREATE DATABASE baza
• Copy of model database is created
C:\...\Data\baza.mdf
C:\...\Data\baza.ldf
Data files
CREATE DATABASE baza ON
(NAME=nazwa,
FILENAME=‘nazwa_pliku’,
SIZE=10MB,
MAXSIZE = 20MB | UNLIMITED
FILEGROWTH = 20% | 2MB),...
LOG ON
(NAME=nazwa,
FILENAME=‘nazwa_pliku’,
SIZE=10MB,
MAXSIZE = 20MB | UNLIMITED
FILEGROWTH = 20% | 2MB),...
Why do we need log?
1
Data modification
Cache
2 Read page from disk
3 Save to log
Disk
Disk
4
Save change to
database
CHECKPOINT
update tematy set nazwa=‘dysk’ where nr>10
insert into pracownicy values(19,’Kowalski’)
update tablica set pole1=‘xyz’ where pole2>10
Transaction log
•
•
•
•
•
•
Every data change is stored in log file first
Every operation has transaction defined
Begins and commits are stored in log
CHECKPOINT – place to which data is stored on disk
Every data write to disk changes CHECKPOINT position
In case of failure – rollback of not commited transaction and
rollforward of commited
Format of datafiles
• Page – 8kB
• Extent – 8 consecutive pages
– Uniform extent – pages from one object
– Mixed extent – contains pages from different
objects
Begining of the file
Header
PFS
GAM
SGAM
Page0: File Header – logical name, prameters (size
chcnge params
Page1: PFS (Page Free Space)– 1 byte about every
page (8000 first pages– 64MB)
Page2: GAM (Global Allocation Map) – bit for every
extend – free or full (64k extents = 2GB)
Page3: SGAM (Shared Global Allocation Map) – bit for
every extent – are there free pages? (64k extents =
2GB)
Meaning of GAM & SGAM bits
Content of extent
Bit GAM
Bit SGAM
Free
1
0
Uniform or full
0
0
Mixed with free pages
0
1
Objects allocation
• IAM page (Index Allocation Map)
– Pointers to first 8 pages
– Bitmap of extents
(for 512 000 pages)
Max values...
Databases
32.767
Databse size
1.048.516 TB
Files for database
32.767
File size
32 TB
Objects in database (tables, views,
2.147.483.647
stored procedures, extended stored procedures,
triggers, rules, defaults, and constraints)
Columns in table
1024
Structure of database
Log
Database
Log
Primary
Filegroup
File.mdf
File.ndf
Filegroup
File.ndf
File.ndf
Division to files
CREATE DATABASE baza ON
PRIMARY (NAME=nazwa,FILENAME=‘nazwa_pliku’,SIZE=10MB,MAXSIZE=20MB
FILEGROWTH = 20%),
(NAME=nazwa,FILENAME=‘nazwa_pliku’,SIZE=10MB,MAXSIZE=20MB FILEGROWTH
= 20%),
FILEGROUP fg1 (
(NAME=nazwa,FILENAME=‘nazwa_pliku’,SIZE=10MB,MAXSIZE=20MB FILEGROWTH
= 20%),
(NAME=nazwa,FILENAME=‘nazwa_pliku’,SIZE=10MB,MAXSIZE=20MB
FILEGROWTH=20%))
Filegroups
• PRIMARY – for system objects
• User-defined – users objects explicitly placed
here using ON filegroup
CREATE TABLE tablica (int pole1,int pole2) ON fg1;
• DEFAULT – default place for objects
Creating new filegroup
ALTER DATABASE baza
ADD FILEGROUP newFG
GO
ALTER DATABASE baza
ADD FILE
(NAME = ‘mojNowyPlik',
FILENAME = 'c:\...\plik.ndf,
SIZE = 5MB)
TO FILEGROUP newFG
GO
Why more than one file?
• Performance
– faster access when more hd's
• Easier to maintain
– small files easier to handle
– backup of important files only
• Protection of data
– read-only files
• Protection of system data
– separate file for system tables
Database parameters
•
•
•
•
•
Auto options
Cursor options
Recovery options
SQL options
State options
Auto options
•
•
•
•
AUTO_CLOSE
AUTO_CREATE_STATISTICS
AUTO_UPDATE_STATISTICS
AUTO_SHRINK
Cursor options
• CURSOR_CLOSE_ON_COMMIT
• CURSOR_DEFAULT
[LOCAL | GLOBAL]
Recovery options
• RECOVERY
– FULL
– BULK_LOGGED
– SIMPLE
• PAGE_VERIFY
– CHECKSUM
– TORN_PAGE_DETECTION
– NONE
Snapshot isolation (2k5)
• ALLOW_SNAPSHOT_ISOLATION
– ON: SNAPSHOT isolation level allowed – transaction sees
data as it was when it started
– OFF: SNAPSHOT isolation level switched off
• READ_COMMITED_SNAPSHOT
– ON: transaction on READ COMMITTED isolation level sees
last committed data – no waits
– OFF: transaction on READ COMMITTED isolation level
locks during dirty read (like in SQL2k)
SQL options
•
•
•
•
•
•
•
ANSI_NULL_DEFAULT
ANSI_NULLS
ANSI_PADDING
ANSI_WARNINGS
ARITHABORT – arithmetic abort
NUMERIC_ROUNDABORT
CONCAT_NULL_YIELDS_NULL
QUOTED_IDENTIFIER
-- doesn’t work!
SET QUOTED_IDENTIFIER OFF
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
-- works fine!
SET QUOTED_IDENTIFIER ON
CREATE TABLE "select" ("identity" int IDENTITY, "order" int)
SELECT "identity","order" FROM "select" ORDER BY "order"
-- always works
CREATE TABLE [select] ([identity] int IDENTITY, [order] int)
SELECT [identity],[order] FROM [select] ORDER BY [order]
-- but it’s not a good idea!
State options
• ON_LINE | OFF_LINE
• READ_ONLY | READ_WRITE
• SINGLE_USER | RESTRICTED_USER |
MULTI_USER
Execution condition
WITH <termination>
• WAIT (default)
• ROLLBACK AFTER 10 [SECONDS]
• ROLLBACK IMMEDIATE
• NO_WAIT
Examples
ALTER DATABASE baza
SET QUOTED_IDENTIFIER ON, RECOVERY FULL, MULTI_USER
GO
ALTER DATABASE baza
SET SINGLE_USER
WITH ROLLBACK AFTER 10
GO
Transact SQL
• Stored procedures
EXEC sp_helpdb
• Functions
SELECT
DATABASEPROPERTYEX(‘baza','IsOnCommitEnabled')
• DBCC
DBCC SQLPERF
DBCC SHRINKFILE
Data types
• Numeric
–
–
–
–
•
•
•
•
Integer
Exact floating point
Floating point
Currency
Date and time
Text
BLOB
Special
Numeric types
int
4
bigint
8
smallint
2
tinyint
1
decimal(p[,s])
2-17
numeric (p[,s])
2-17
float(n)
n(1-24) 7 digits – 4B
n(25-53) 15 digits – 8B
real
4
money
8
smallmoney
4
Date and text types
datetime
8
smalldatetime
4
char(n)
0-8000
varchar(n)
0-8000
nchar(n)
0-8000 (4000 chars!)
nvarchar(n)
0-8000 (4000 chars!)
binary
0-8000
varbinary
0-8000
Other types
image
0-2 GB
text
0-2 GB
ntext
0-2 GB
uniqueidentifier
16
bit
1
timestamp
8
sql_variant
up to 8000
User defined types
• Type creation
EXEC sp_addtype nazwisko, 'nvarchar(25)', NULL
• Type deletion
EXEC sp_droptype nazwisko
Data row organization
Header
Normal fields
Null
Block
Variable
Block
Variable length fields
• Header – 4 bytes
• Null block – 2B for columns number, Null Bitmap (1
bit for column – if its null)
• Variable block – 2B for columns number, 2B for
column with pointer to column position
• Max row length – 8060 B
Storing BLOBs
• Special tree structures
• It can be defined how big value will be directly
in row.
EXEC sp_tableoption 'tablica', 'text in row', '1000'
• Max row size: 8060 B. Big BLOBs are stored
as pointers (16B)
IDENTITY column
• One in table
• Definition: IDENTITY[(seed,incr)]
CREATE TABLE pracownicy (
nr_prac int IDENTITY(100,1),
nazwisko varchar(30)))
insert into pracownicy values (‘Kowalski’);
insert into pracownicy values (‘Nowak’);
insert into pracownicy values (‘Iksiński’);
nr_prac
----------100
101
102
nazwisko
---------Kowalski
Nowak
Iksiński
IDENTITY control
• select IDENT_CURRENT('table') – globally highest value of the
column
• select @@identity – last value inserted in the session (NULL if
nothing was inserted)
• select IDENT_SEED(‘table’)
• select IDENT_INCR(‘table’)
• select SCOPE_IDENTITY() – last IDENTITY value inserted (to
any table)
Disabling IDENTITY
nrp int IDENTITY(100,1),
nazw varchar(30)))
insert into pracownicy(nazw) values (‘Kowalski’);
SET IDENTITY_INSERT pracownicy ON
insert into pracownicy(nrp,nazw) values (200,‘Nowak’);
SET IDENTITY_INSERT pracownicy OFF
insert into pracownicy(nazw) values (‘Iksiński’);
nr_prac
----------100
200
201
nazwisko
---------Kowalski
Nowak
Iksiński
Not-unique IDENTITY
nrp int IDENTITY(100,1),
nazw varchar(30)))
SET IDENTITY_INSERT pracownicy ON
insert into pracownicy(nrp,nazw) values (100,‘Nowak’);
SET IDENTITY_INSERT pracownicy OFF
nr_prac
----------100
101
100
nazwisko
---------Kowalski
Iksiński
Nowak
Uniqueidentifier type
• 16B (128b) – GLOBALLY unique (GUID)
nrp uniqueidentifier NOT NULL DEFAULT newid(),
nazw varchar(30)))
insert into pracownicy(nazw) values (‘Nowak’);
nr_prac
-----------------------------------075860D6-FBAC-466E-A0F5-5EAF0D69543B
A5B7C0BD-0F23-4F79-9758-AF35A6D20D3D
FF8BEBC6-21F8-46A1-8108-8507BA9509E0
nazwisko
---------Kowalski
Iksiński
Nowak
timestamp (rowversion)
CREATE TABLE tt (a int, b timestamp)
insert into tt(a) values (1);
insert into tt(a,b) values(2,null)
a
----------1
2
b
-----------------0x00000000000000CC
0x00000000000000CD
update tt set a=3 where a=1
a
----------3
2
b
-----------------0x00000000000000CF
0x00000000000000CD
CONSTRAINTS
•
•
•
•
•
•
Default
Check
Primary Key
Unique
Foreign Key
CREATE DEFAULT
Default constraints
• Not for IDENTITY
• Works only for inserts
• We may use variables or system functions: newid(), user,
getdate()
CREATE TABLE tablica(
tekst varchar(50),
wpisal varchar(30) default user,
data_wpisu datetime default getdate()
)
insert into tablica(tekst) values(‘Nowy tekst’)
tekst
wpisal
data_wpisu
------------ ---------------- ----------------------Nowy tekst
pawel
2004-10-10 20:52:02.513
Check constraint
• Works for every data change
CREATE TABLE pracownicy(
pensja int check (pensja>0),
data_ur datetime,
opis varchar(50),
constraint data_mniejsza check(data_ur<getdate()))
insert into pracownicy values(10,’2100’,’’)
INSERT statement conflicted with COLUMN CHECK constraint
'data_mniejsza'.
insert into pracownicy values(-10,’1980’,’’)
INSERT statement conflicted with COLUMN CHECK constraint
'CK__pracownic__pensj__7E6CC920'.
Check constraint
• May be used for more than one column
CREATE TABLE projekty (
start datetime,
koniec datetime,
constraint koniec_po_starcie check (start<koniec))
• Logic values may be used
ALTER TABLE tablica
ADD
CONSTRAINT dataur
CHECK (dataur>'01-01-1900' AND dataur<getdate())
Check constraint
• Usage of patterns
CREATE TABLE adresy (
miasto varchar(30),
kod char(6) check(kod LIKE '[0-9][0-9]-[0-9][0-9][0-9]'),
ulica varchar(40) check(ulica like '[a-z]%[0-9]')
)
insert
insert
insert
insert
into
into
into
into
adresy
adresy
adresy
adresy
values(’Gliwice','22-445',‘Ala 6')
values(’Gliwice','22-44',‘Ala 6')
values(’Gliwice','22-442',‘5Ala 6')
values(’Gliwice','22-442',‘5 Ewa')
NOCHECK
• Doesn’t check constraints on already inserted
columns
CREATE TABLE tablica ( a INT);
INSERT INTO tablica VALUES (-1);
ALTER TABLE tablica
ADD CONSTRAINT mycheck CHECK (a > 1);
ALTER TABLE statement conflicted with COLUMN CHECK constraint
'mycheck'.
ALTER TABLE tablica WITH NOCHECK
ADD CONSTRAINT mycheck CHECK (a > 1);
The command(s) completed successfully.
Primary key
• One in one table (may be more than one column)
• Automatic index creation
CREATE TABLE tablica (
a INT [[NON]CLUSTERED] PRIMARY KEY,
b varchar(20));
a INT ,
b varchar(20),
PRIMARY KEY (a));
ALTER TABLE tablica
ADD CONSTRAINT primary_key
PRIMARY KEY NONCLUSTERED (a);
Unique
•
•
•
•
May have one NULL value
May be more than one in table
Cannot use it with PK columns
Automatic index creation
Foreign key
• No SET NULL
• May be for more than one column
• WITH NOCHECK may be used
a INT,
b varchar(20),
PRIMARY KEY (a,b));
CREATE TABLE tab2(
x int,
y varchar(20),
foreign key (x,y) references tablica(a,b)
on update cascade);
Turning off constraints
When big amount of data is loaded
• When we know they fulfill conditions
• When they are not but it is easier to correct it
in the database
ALTER TABLE tablica
NOCHECK CONSTRAINT mój_warunek
... Data loading ...
ALTER TABLE tablica
CHECK CONSTRAINT mój_warunek
CREATE DEFAULT
• One definition used in different places (also in
user types)
CREATE DEFAULT mojkraj AS ‘Polska’
sp_bindefault mojkraj, ‘pracownicy.kraj'
sp_bindefault mojkraj, ‘studenci.kraj'
sp_bindefault mojkraj, ‘adresy.kraj'
• Turning off default
sp_unbindefault mojkraj, ‘adresy.kraj'
Computed columns
create table prac(nrp int,
adr_domowy varchar(30), adr_praca varchar(30),
koresp int,
adr_koresp as CASE koresp
WHEN 0 THEN adr_domowy
ELSE adr_praca END
)
insert into prac values(1,'Chorzów','Gliwice',0)
select * from prac
nrp adr_domowy
adr_praca
koresp adr_koresp
--- ------------ ----------- ------ ----------1
Chorzów
Gliwice
0
Chorzów
update prac set koresp=1
select * from prac
nrp adr_domowy
adr_praca
koresp adr_koresp
--- ------------ ----------- ------ ----------1
Chorzów
Gliwice
1
Gliwice
SQL and indexes
• Index creation
create index nazwa on tablica(kolumna,...)
create unique index nazwa on tablica(kolumna,...)
create clustered index nazwa on tablica(kolumna,...)
create unique clustered index nazwa on
tablica(kolumna,...)
• Index dropping
drop index tablica.nazwa
How to use indexes
•
•
•
•
•
PK and UNIQUE are better
First clustered
Do not duplicate indexes!
Indexed fields should be short
Use UNIQUE – if it is possible
SELECT id, COUNT(*) FROM tablica
GROUP BY id
HAVING COUNT(*)>1
Indexes pros and cons
• Pros:
– Faster data searching
– Control of data uniqueness
• Cons:
–
–
–
–
Slower data insertion
Slower updates of indexed columns
Storage (depends on column size)
Difficult database administration
Composite indexes
• Max 16 columns (900 bytes)
• Order is important!
create index xyz on prac(nazw,imie)
create index xyz on prac(imie,nazw)
• First the most unique column
• Index is used only when query has first
column in WHERE column!
FILLFACTOR option
• States how to fill pages
• Default 100%
• Decreasing increases disk storage but simplifies
insert and update
• Without PAD_INDEX used only for leaves
create index xyz on prac(nazw,imie)
with [PAD_INDEX,] FILLFACTOR=70
DBCC application
•
•
•
•
•
•
•
DBCC – Database Consistency Checker
About 130 different operations
DBCC checkdb
DBCC cleantable
DBCC perflog
DBCC showcontig
DBCCC indexdefrag
DBCC showcontig
DBCC SHOWCONTIG scanning 'tablica' table...
Table: 'tablica' (2073058421); index ID: 1, database ID: 6
TABLE level scan performed.
Pages Scanned: 3
Extents Scanned: 2
Extent Switches: 1
Avg. Pages per Extent: 1.5
Scan Density [Best Count:Actual Count]: 50.00% [1:2]
Logical Scan Fragmentation 0.00%
Extent Scan Fragmentation: 50.00%
Avg. Bytes Free per Page: 246.7
Avg. Page Density (full): 96.95%
DBCC execution completed. If DBCC printed error messages,
contact your system administrator.

SQL Server

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