Wednesday, February 24, 2010

Tracking Changes in Your Enterprise Database

Tracking Changes in Your Enterprise Database

Thursday, February 18, 2010

ASCII Character Codes

ASCII Character Codes

Is ISOLATION LEVEL READ UNCOMMITTED same as WITH (NOLOCK)

In one word, YES they are the same.

Transactions running at the READ UNCOMMITTED level do not issue shared locks to prevent other transactions from modifying data read by the current transaction. READ UNCOMMITTED transactions are also not blocked by exclusive locks that would prevent the current transaction from reading rows that have been modified but not committed by other transactions. When this option is set, it is possible to read uncommitted modifications, which are called dirty reads. Values in the data can be changed and rows can appear or disappear in the data set before the end of the transaction. This option has the same effect as setting NOLOCK on all tables in all SELECT statements in a transaction. This is the least restrictive of the isolation levels.

Check here for more detailed information


Also here is another document :
Read Committed Isolation Level

Find out all FK CONSTRAINT that exist on a table

declare @tableName varchar(200)
set @tableName = 'ssis_tasks'

select * from sys.foreign_keys k
inner join sys.tables t on t.[object_id] = k.referenced_object_id
where t.[name] = @tableName

SELECT * FROM INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE where CONSTRAINT_NAME in
(
select k.name from sys.foreign_keys k
inner join sys.tables t on t.[object_id] = k.referenced_object_id
where t.[name] = @tableName
)

Thursday, February 11, 2010

Run SP automatically when SQL Server starts

EXECUTE sp_procoption
@procname = 'usp_StartTrace',
@optionname = 'startup',
@optionvalue = 'on'

Identify Primary Keys and PK column name

SELECT KU.*
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS TC
INNER JOIN
INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KU
ON TC.CONSTRAINT_TYPE = 'PRIMARY KEY' AND
TC.CONSTRAINT_NAME = KU.CONSTRAINT_NAME
ORDER BY KU.TABLE_NAME, KU.ORDINAL_POSITION

Tuesday, February 09, 2010

Change Tracking with SQL 2008

USE [Test]
GO

DROP TABLE [ChangeTrack]
GO

CREATE TABLE [dbo].[ChangeTrack](
[LineID] [int] IDENTITY(1000,1) NOT NULL,
[Fname] [nvarchar](100) NULL,
[Lname] [nvarchar](100) NULL,
[InsertDate] [datetime] NULL,
CONSTRAINT [PK_ChangeTrack] PRIMARY KEY CLUSTERED
(
[LineID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[ChangeTrack] ADD CONSTRAINT [DF_ChangeTrack_InsertDate] DEFAULT (getdate()) FOR [InsertDate]
GO
ALTER TABLE [dbo].[ChangeTrack] ENABLE CHANGE_TRACKING WITH(TRACK_COLUMNS_UPDATED = ON)
GO

declare @synchronization_version bigint , @last_synchronization_version bigint

set @last_synchronization_version = CHANGE_TRACKING_CURRENT_VERSION()
waitfor delay '00:00:05'

--load table
insert into [ChangeTrack] (Fname, Lname ) values ('Pat','Rick'), ('Pat','Rick'),('Pat','Rick'),('Pat','Rick'),('Pat','Rick'),('Pat','Rick'),('Pat','Rick'),('Pat','Rick'),('Pat','Rick'),('Pat','Rick')
waitfor delay '00:00:05'

--Obtain initial data set.
--SELECT * FROM [ChangeTrack]


--Using the Change Tracking Functions to Obtain Changes
--declare @last_synchronization_version bigint
--set @last_synchronization_version = 1302
set transaction isolation level snapshot
begin transaction
SELECT
Getdate(), CT.[LineID], CT.SYS_CHANGE_OPERATION,
CT.SYS_CHANGE_COLUMNS, CT.SYS_CHANGE_CONTEXT
FROM
CHANGETABLE(CHANGES [ChangeTrack], @last_synchronization_version) AS CT

set @last_synchronization_version = CHANGE_TRACKING_CURRENT_VERSION()
commit
/*
SELECT
CT.[LineID], P.*,
CT.SYS_CHANGE_OPERATION, CT.SYS_CHANGE_COLUMNS,
CT.SYS_CHANGE_CONTEXT
FROM
[ChangeTrack] AS P
RIGHT OUTER JOIN
CHANGETABLE(CHANGES [ChangeTrack], @last_synchronization_version) AS CT
ON
P.[LineID] = CT.[LineID]
*/
--select CHANGE_TRACKING_CURRENT_VERSION();
waitfor delay '00:00:05'

--some updates
update [ChangeTrack] set Fname = Fname + '_CHANGED' where LineID % 10 = 4
waitfor delay '00:00:05'

--Using the Change Tracking Functions to Obtain Changes
--declare @last_synchronization_version bigint
--set @last_synchronization_version = 1312
set transaction isolation level snapshot
begin transaction
SELECT
Getdate(), CT.[LineID], CT.SYS_CHANGE_OPERATION,
CT.SYS_CHANGE_COLUMNS, CT.SYS_CHANGE_CONTEXT
FROM
CHANGETABLE(CHANGES [ChangeTrack], @last_synchronization_version) AS CT

set @last_synchronization_version = CHANGE_TRACKING_CURRENT_VERSION()
commit
/*
SELECT
CT.[LineID], P.*,
CT.SYS_CHANGE_OPERATION, CT.SYS_CHANGE_COLUMNS,
CT.SYS_CHANGE_CONTEXT
FROM
[ChangeTrack] AS P
RIGHT OUTER JOIN
CHANGETABLE(CHANGES [ChangeTrack], @last_synchronization_version) AS CT
ON
P.[LineID] = CT.[LineID]
*/
--select CHANGE_TRACKING_CURRENT_VERSION();
waitfor delay '00:00:05'

--some insert/update/delete
insert into [ChangeTrack] (Fname, Lname ) values ('Pat111','Rick111'),('Pat111','Rick111'),('Pat111','Rick111'),('Pat111','Rick111'),('Pat111','Rick111')
update [ChangeTrack] set Fname = '123' where LineID % 10 = 5
delete from [ChangeTrack] where LineID % 10 = 6
waitfor delay '00:00:05'

--select * from [ChangeTrack]

--Using the Change Tracking Functions to Obtain Changes
--declare @last_synchronization_version bigint
--set @last_synchronization_version = 1313
set transaction isolation level snapshot
begin transaction
SELECT
Getdate(), CT.[LineID], CT.SYS_CHANGE_OPERATION,
CT.SYS_CHANGE_COLUMNS, CT.SYS_CHANGE_CONTEXT
FROM
CHANGETABLE(CHANGES [ChangeTrack], @last_synchronization_version) AS CT

set @last_synchronization_version = CHANGE_TRACKING_CURRENT_VERSION()
commit
/*
SELECT
CT.[LineID], P.*,
CT.SYS_CHANGE_OPERATION, CT.SYS_CHANGE_COLUMNS,
CT.SYS_CHANGE_CONTEXT
FROM
[ChangeTrack] AS P
RIGHT OUTER JOIN
CHANGETABLE(CHANGES [ChangeTrack], @last_synchronization_version) AS CT
ON
P.[LineID] = CT.[LineID]
*/
--select CHANGE_TRACKING_CURRENT_VERSION()

PIVOT , UNPIVOT

--Create the table and insert values as portrayed in the previous example.
CREATE TABLE pvt (VendorID int, Emp1 int, Emp2 int,
Emp3 int, Emp4 int, Emp5 int);
GO
INSERT INTO pvt VALUES (1,4,3,5,4,4);
INSERT INTO pvt VALUES (2,4,1,5,5,5);
INSERT INTO pvt VALUES (3,4,3,5,4,4);
INSERT INTO pvt VALUES (4,4,2,5,5,4);
INSERT INTO pvt VALUES (5,5,1,5,5,5);
GO

select * from pvt

--Unpivot the table.
SELECT VendorID, Employee, Orders
into #tmp
FROM
(SELECT VendorID, Emp1, Emp2, Emp3, Emp4, Emp5
FROM pvt) p
UNPIVOT
(Orders FOR Employee IN
(Emp1, Emp2, Emp3, Emp4, Emp5)
)AS unpvt;
GO

select * from #tmp
select * from pvt

-- pivot table
select *
from #tmp
pivot
(
sum(orders)
for employee in (Emp1, Emp2, Emp3, Emp4, Emp5)
) as p

---------------------------
--dynamic creation
declare @str nvarchar(1000)
set @str = ''
select @str = @str + employee+ ',' from #tmp group by employee
set @str = left(@str, LEN(@str)-1)
select @str

declare @sql nvarchar(1000)
set @sql = '
select *
from #tmp
pivot
(
sum(orders)
for employee in ('+@str+')
) as p'

print @sql
exec sp_executesql @sql
---------------------------

Monday, February 01, 2010

Data Type GEOMETRY usage to draw my face

SELECT geometry::Point(x, y, 0).STBuffer(0.4) As sig
FROM ( VALUES
(02,16),(02,17),(02,19),(02,20),(02,25),(02,26),(02,27),(02,28),(03,29),(03,30),(02,31),(02,32),(02,33),
(03,15),(03,22),(03,23),(03,24),(03,26),(03,27),(03,28),(03,29),(03,30),(03,31),(03,32),(03,33),(03,34),(03,35),(03,36),
(04,31),(04,32),(04,33),(04,34),(04,35),(04,36),(04,37),
(05,35),(05,36),(05,37),(05,38),(05,39),(05,40),
(06,23),(06,26),(06,37),(06,38),(06,39),(06,40),
(07,23),(07,24),(07,26),(07,38),(07,39),(07,40),(07,41),
(08,16),(08,22),(08,23),(08,24),(08,26),(08,27),(08,40),(08,41),(08,42),
(09,12),(09,13),(09,23),(09,24),(09,26),(09,27),(09,41),
(10,12),(10,13),(10,23),(10,24),(10,25),(10,26),(10,27),(10,43),
(11,13),(11,23),(11,24),(11,25),(11,39),(11,41),
(12,02),(12,13),(12,22),(12,23),(12,25),(12,38),(12,39),(12,40),(12,41),
(13,01),(13,02),(13,10),(13,13),(13,16),(13,17),(13,39),(13,40),(13,41),(13,42),
(14,01),(14,02),(14,07),(14,12),(14,39),(14,40),(14,41),(14,42),
(15,01),(15,07),(15,39),(15,40),(15,41),(15,42),(15,43),
(16,01),(16,15),(16,40),(16,41),(16,42),(16,43),
(17,01),(17,10),(17,16),(17,40),(17,41),(17,42),(17,43),
(18,01),(18,10),(18,13),(18,16),(18,40),(18,41),(18,42),(18,43),
(19,01),(19,10),(19,13),(19,16),(19,23),(19,24),(19,25),(19,39),(19,40),(19,41),(19,42),
(20,01),(20,06),(20,10),(20,11),(20,12),(20,22),(20,23),(20,24),(20,25),(20,26),(20,40),(20,41),(20,42),
(21,02),(21,03),(21,05),(21,06),(21,11),(21,12),(21,22),(21,23),(21,24),(21,25),(21,26),(21,40),(21,41),(21,42),
(22,02),(22,03),(22,12),(22,16),(22,17),(22,22),(22,23),(22,26),(22,27),(22,40),(22,41),
(23,03),(23,04),(23,05),(23,06),(23,12),(23,23),(23,24),(23,27),(23,40),(23,41),
(24,04),(24,05),(24,23),(24,24),
(25,04),(25,05),(25,06),(25,23),(25,24),(25,27),
(26,05),(26,06),(26,07),(26,23),(26,27),
(27,06),(27,07),(27,37),(27,38),(27,39),
(28,07),(28,22),(28,23),(28,24),(28,28),(28,29),(28,30),(28,31),(28,32),(28,35),(28,36),(28,37),(28,38),(28,39),
(29,08),(29,09),(29,24),(29,26),(29,27),(29,28),(29,29),(29,30),(29,31),(29,32),(29,33),(29,34),(29,35),(29,36),(29,37),(29,38),
(30,12),(30,28),(30,29),(30,30),(30,31),(30,32),(30,33),(30,34),(30,35),(30,36),
(31,12),(31,17),(31,18),(31,19),(31,20),(31,21),(31,22),(31,23),(31,24),(31,25),(31,26),(31,27),(31,28),(31,29),(31,30),(31,31),(31,32),(31,33),
(32,21),(32,22),(32,23),(32,24),(32,25),(32,26),(32,27),(32,28)

) AS Coordinates(x, y);
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