Log shipping from Sql Server 2008r2 to Sql Server 2008R2
Log shipping from one server to another server is an option that a DBA has, for high arability in Sql Server.
It’s very much like Oracle data guard where from primary to standby archive redo logs goes and are applied automatically. Comparing to Oracle, I would say its lot easy to configure and troubleshoot.
Following are the pre-requisites of log shipping.
Primary database should be running in Full or Bulk recovery mode
Create a shared folder to store backup of transaction logs
We can use either SSMS or using T-Sql, I have discussed SSMS methods following.
Right click on the database and choose property options
From property option select “Transaction Log Shipping”
Select “Enable this as a primary database in a log shipping configuration” check box
Select “backup setting” under “transaction log backup”
In “network path to backup folder” provide path of shared network folder where backup files will be stored.
Now click on “Add” option and it will bring you to new page that asks for connection to your secondary database. Click on “Connect” button and provide logon information of your server hosting secondary database.
In “Initialize Secondary database” tab select first radio button if you want your secondary database to be created from scratch.
In “Copy files” option provide the path of locally created folder.
In “Restore Transaction Log” option choose standby mode and click ok. This will take you back at “Transaction log shipping page”
Optionally you can provide information of monitoring instance.
Now! That’s all you need to set up a Primary/Standby or Primary/Secondary database in SQL server.
This whole setup has created 4 jobs. 1 in primary database and 3 in secondary database. Following I have discussed the jobs.
The “Backup” job created in Primary site, would take backup of transactional log periodically. Sql Server agent put the backup files to designated shared folder.
The “Copy” job created in secondary site, would copy the backup logs from shared folder to local machine.
The “Restore” job would periodically restore the backup on secondary site and keep secondary database in sync with primary database.
The “Alert” job sends alerts at each event.
Any correction,suggestion would be appreciated.
Thanks and regards,
Wednesday 10 September 2014
Sunday 24 August 2014
SQL Server 2012 in-built functions
Hi,
In this blog, I have discussed Sql Server in-built functions to be used in T-sql, queries, DML's. I have detailed them and have provided example of each function. Any suggestion,correction would be highly appriciated.
--Math Functions
--Average function
Select avg(Person_id) avg from db_owner.person
--CharIndex function to find index of a particular alphabet. In example
--CHARTINDEX finds 'a' in first_name column of person starting from 1st character of
--string
Select CHARINDEX('a',First_Name,1)a,first_name from db_owner.Person
Use MS2012;
go
declare @avar xml
RETURN @avar.query('Product/Prices')
truncate table db_owner.person
delete * from db_owner.person where middle_name is null
create table t1(id int identity(1,1) default 1)
select * from db_owner.person
select sum(person_id),count(*) ,first_name from db_owner.person
select top(10)
desc sp_settrigger
declare @var1 nvarchar(20);
select @var1 ='My Example';
Select CharIndex ('m',@var1,1) Col1,
CharIndex('P',@var1,1) COl2,
CharIndex ('x',@var1,1) Col3
GO
---Concat Function
Select ConCat ('Mr.',' Jaidev ',' sharma')
Select Concat(First_name,'--',Last_name) from db_owner.Person
---Left function shows number of character from left side of string
-- in example first four character from left would be displayed
Select Left('jaidev sharma',4)
--Len function to get the total length of a string
Select len('jaidev')
Select len(first_name) leth,First_Name from db_owner.person
---Lowever and upper
Select lower('Jaidev'),upper('jaidev')
Select lower(first_name),upper(Last_Name) from db_owner.person
---Ltrim,Rtrim,trim removes blank spaces
select Ltrim(' jaidev')y,Rtrim('Jaidev ')x
Declare @var1 nvarchar(50);
set @var1 = ' My Name is Jaidev Sharma';
Select Ltrim(@var1)
--Substring to get a portion of a string starting from 2nd parameter and upto
--3rd parameter
Select substring('Jaidev',3,3)
Select First_Name,SubString(First_name,1,len(first_name)) nm from db_owner.person
--Find a particular characher left and right of a string
Select PATINDEX(lower('%S%'),'Australia')
Select First_name from db_owner.person
Select PatIndex('%o%',First_Name),First_Name from db_owner.Person
----Replace find a particular character give in 2nd parameter and replaces it
---a parameter give in 3 parameter. In example in 'jai' string 'a' is replaced with 'u'
---
Select Replace('jai','a','u')
Select First_name,Replace(First_name,'a','h') from db_owner.person
Select count(person_id) emp_count from db_owner.person
---++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
---TSQL Date and Time Data Types and Functions
Select @@DATEFIRST
--to get current_Timestamp
Select CURRENT_TIMESTAMP
--to add date in one particular date. In example 1, I have added DAY,41 (no. of days) in to 16-Jun-2014 to see counting 41 from 16-jun what date
--would fall.
---eg 1
Select DATEADD(day,41,'2014-06-16')
--eg 2 in this I have added Month 1 (one month) in todays date
Select DateAdd(Month,1,SysDateTime())
--eg3 In this I have added Year 1 ( one year) in the today's date.
Select DateAdd(Year,1,SysDateTime())
---DateDiff function tells us the difference between to dates.
Select DateDiff(day,'2014-06-16','2014-07-28') --42 days
Select DateDiff(Month,'2014-06-16','2014-07-28') --1 month
Select DateDiff(Year,'2014-06-16','2014-07-28')
---DATEFROMPARTS
Select DateFromparts(1,2,3)
----DATENAME return a specific information (eg. Year,Month,Day, Day of Year or week) of a date. To get just year portion of date use year,
Select DateName(Year,CURRENT_TIMESTAMP) year
Select DateName(Month,CURRENT_TIMESTAMP) Month
Select DateName(day,Current_TimeStamp) Day
Select DateName(DayOfYear,Current_TimeStamp) Day_Of_Year
Select DateName(Week,Current_TimeStamp) WeekNo
----DATEPART Similar to DateName
Select DatePart(Month,Current_TimeStamp) Month
Select DatePart(Year,Current_Timestamp) Year
Select DatePart(Day,Current_TimeStamp) Day
--DATETIMEFROMPARTS converts integers in Data Format
Select DateTimeFromParts(2014,3,22,13,22,13,14) Dat1
--DATETIME2FROMPARTS
---Select DATETIME2FROMPARTS(2014,3,12,12,03,20,12,1)
SELECT DATETIME2FROMPARTS(2014, 2, 22, 8, 53, 39, 7, 1) as Date_1
--DAY to know current day of the month
Select day(current_timestamp)
--EOMONTH end of month
Select EoMonth(CURRENT_TIMESTAMP)
-- GETDATE()
Select GetDate()
--GETUTCDATE()
Select GETUTCDATE()
---ISDATE checks the format of date. If format is right than it return 1 otherwise 0
Select IsDate('14-03-02')-- Returns 0 as date format is wrong
Select SYSDATETIME()
Select IsDate(CURRENT_TIMESTAMP) --Returns 1 as date format provided by Current_TImeStamp is right
---- MONTH
Select MONTH(current_timestamp)
Select year(CURRENT_TIMESTAMP)
--SmallDateTimeFromParts
Select SMALLDATETIMEFROMPARTS(2014,07,29,1,04)
--SWITCHOFFSET
--- SYSDATETIME returnes system time stamp
Select SysDateTime()
-- SYSDATETIMEOFFSET
-- SYSUTCDATETIME
-- TIMEFROMPARTS
-- TODATETIMEOFFSET
----TSQL System Functions
---
select @@CONNECTIONS,getdate();
--@@Error to knowif error any came
Use Ms2012;
Go
Select * from db_owner.gender;
Update db_owner.Gender set Gender='UnKnown' where Gender_id=3;
delete from db_owner.gender where Gender_id=4;
if @@ERROR <> 0 Print N'There is no Gender Id 4'
Select * from db_owner.gender;
GO
-- @@IDENTITY to know last value IDENTITY value inserted
-- @@ROWCOUNT to see number of rows effected by a T-Sql Statement
use MS2012;
go
Update db_owner.gender set Gender='Male' where Gender_id=1;
Update Db_owner.Gender set gender='Female' Where Gender_id=2;
Update Db_owner.Gender set gender='Unkown' Where Gender_id=3;
if @@ROWCOUNT<> 0
print Concat('The number of rows affected are ' , @@Rowcount);
if @@ROWCOUNT=0
Print Concat(@@ROWCOUNT, ' no row effected' );
Select * from db_owner.gender;
go
-- COALESCE equal to NVL function of Oracle
Alter Table Db_owner.person
alter column middle_name nvarchar(20) null
Select * from db_owner.person
Update db_owner.Person set Middle_name=null where Person_id=103
Select First_name,Coalesce(Middle_name,null,'UnKown') from db_owner.Person
--ERROR_LINE returns the error at particular line when using with Try and Catch block
USE model;
GO
BEGIN TRY
SELECT 8/0;
END TRY
BEGIN CATCH
SELECT ERROR_LINE() AS ErrorLine;
Select ERROR_MESSAGE () As ErrorMessage
Select ERROR_NUMBER () As ErrorNumber
Select ERROR_PROCEDURE() as Proce
Select ERROR_SEVERITY () as Sever
Select ERROR_STATE() as Stat
END CATCH;
GO
/* ERROR_MESSAGE
ERROR_NUMBER
ERROR_PROCEDURE
ERROR_SEVERITY
ERROR_STATE*/
---Host_Id
Select HOST_ID() as HostId
---HOST_NAME
Select Host_name() HostName
---IsNull
Select ISNULL(NUll,'Jai')
Select * from db_owner.person
select IsNull(Middle_name,'Kumar (replaced)'),Middle_name from db_owner.person
---ISNUMERIC either 1 or 0 if 1 than parameter is number
Select ISNUMERIC('a')
--- NULLIF checks if two expressions are same or not. If same than returns
--null otherwise value of first parameter
Select NullIf('a','a') col1,NullIf('a','b'),NullIf('jai','jai')
----Security Functions
--- CURRENT_USER if connect by windows authentication or sa than its show DBO.
Select Current_user as currentUser
Select ORIGINAL_LOGIN() as OrgLogin
--Session user shows the user of sesison. normally it s same as current user function.
Select SESSION_USER
--Shows the user at OS level connected to sql server
Select SYSTEM_USER
--User_Name tell the name of user at sql server level
Select USER_NAME()
TSQL Metadata Functions
--App_Name() gives the name of the applicaiton.In following example it gives 'Microsoft Sql Server Management Stuido - Query' output
Select APP_NAME ()
--DB_ID returns the number assigned to a database
Select DB_ID()
--DB_Name name of database
Select DB_NAME() DBNAMe
---Object_Definition gets the definition of an object
Select * from sys.objects
where name='PERSON'
select * from ms2012.db_owner.gender
Select OBJECT_DEFINITION(object_ID('ms2012.db_owner.gender'))
--Object_id to know the object id
Select Object_id('ms2012.db_owner.person')
--Ojbect Name to know the object name
Select OBJECT_NAME(437576597),Object_id('ms2012.db_owner.person')
Select OBJECT_SCHEMA_NAME(437576597,8)
Select SCHEMA_ID('db_owner')
Select SCHEMA_NAME(16384)
---TSQL Configuration Functions
Select @@LOCK_TIMEOUT as TimeOutOfLog
Select @@MAX_CONNECTIONS as MaxConn
Select @@SERVERNAME as SrvrNm
Select @@SERVICENAME as SrvcNm
select @@SPID as SPID
In this blog, I have discussed Sql Server in-built functions to be used in T-sql, queries, DML's. I have detailed them and have provided example of each function. Any suggestion,correction would be highly appriciated.
--Math Functions
--Average function
Select avg(Person_id) avg from db_owner.person
--CharIndex function to find index of a particular alphabet. In example
--CHARTINDEX finds 'a' in first_name column of person starting from 1st character of
--string
Select CHARINDEX('a',First_Name,1)a,first_name from db_owner.Person
Use MS2012;
go
declare @avar xml
RETURN @avar.query('Product/Prices')
truncate table db_owner.person
delete * from db_owner.person where middle_name is null
create table t1(id int identity(1,1) default 1)
select * from db_owner.person
select sum(person_id),count(*) ,first_name from db_owner.person
select top(10)
desc sp_settrigger
declare @var1 nvarchar(20);
select @var1 ='My Example';
Select CharIndex ('m',@var1,1) Col1,
CharIndex('P',@var1,1) COl2,
CharIndex ('x',@var1,1) Col3
GO
---Concat Function
Select ConCat ('Mr.',' Jaidev ',' sharma')
Select Concat(First_name,'--',Last_name) from db_owner.Person
---Left function shows number of character from left side of string
-- in example first four character from left would be displayed
Select Left('jaidev sharma',4)
--Len function to get the total length of a string
Select len('jaidev')
Select len(first_name) leth,First_Name from db_owner.person
---Lowever and upper
Select lower('Jaidev'),upper('jaidev')
Select lower(first_name),upper(Last_Name) from db_owner.person
---Ltrim,Rtrim,trim removes blank spaces
select Ltrim(' jaidev')y,Rtrim('Jaidev ')x
Declare @var1 nvarchar(50);
set @var1 = ' My Name is Jaidev Sharma';
Select Ltrim(@var1)
--Substring to get a portion of a string starting from 2nd parameter and upto
--3rd parameter
Select substring('Jaidev',3,3)
Select First_Name,SubString(First_name,1,len(first_name)) nm from db_owner.person
--Find a particular characher left and right of a string
Select PATINDEX(lower('%S%'),'Australia')
Select First_name from db_owner.person
Select PatIndex('%o%',First_Name),First_Name from db_owner.Person
----Replace find a particular character give in 2nd parameter and replaces it
---a parameter give in 3 parameter. In example in 'jai' string 'a' is replaced with 'u'
---
Select Replace('jai','a','u')
Select First_name,Replace(First_name,'a','h') from db_owner.person
Select count(person_id) emp_count from db_owner.person
---++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
---TSQL Date and Time Data Types and Functions
Select @@DATEFIRST
--to get current_Timestamp
Select CURRENT_TIMESTAMP
--to add date in one particular date. In example 1, I have added DAY,41 (no. of days) in to 16-Jun-2014 to see counting 41 from 16-jun what date
--would fall.
---eg 1
Select DATEADD(day,41,'2014-06-16')
--eg 2 in this I have added Month 1 (one month) in todays date
Select DateAdd(Month,1,SysDateTime())
--eg3 In this I have added Year 1 ( one year) in the today's date.
Select DateAdd(Year,1,SysDateTime())
---DateDiff function tells us the difference between to dates.
Select DateDiff(day,'2014-06-16','2014-07-28') --42 days
Select DateDiff(Month,'2014-06-16','2014-07-28') --1 month
Select DateDiff(Year,'2014-06-16','2014-07-28')
---DATEFROMPARTS
Select DateFromparts(1,2,3)
----DATENAME return a specific information (eg. Year,Month,Day, Day of Year or week) of a date. To get just year portion of date use year,
Select DateName(Year,CURRENT_TIMESTAMP) year
Select DateName(Month,CURRENT_TIMESTAMP) Month
Select DateName(day,Current_TimeStamp) Day
Select DateName(DayOfYear,Current_TimeStamp) Day_Of_Year
Select DateName(Week,Current_TimeStamp) WeekNo
----DATEPART Similar to DateName
Select DatePart(Month,Current_TimeStamp) Month
Select DatePart(Year,Current_Timestamp) Year
Select DatePart(Day,Current_TimeStamp) Day
--DATETIMEFROMPARTS converts integers in Data Format
Select DateTimeFromParts(2014,3,22,13,22,13,14) Dat1
--DATETIME2FROMPARTS
---Select DATETIME2FROMPARTS(2014,3,12,12,03,20,12,1)
SELECT DATETIME2FROMPARTS(2014, 2, 22, 8, 53, 39, 7, 1) as Date_1
--DAY to know current day of the month
Select day(current_timestamp)
--EOMONTH end of month
Select EoMonth(CURRENT_TIMESTAMP)
-- GETDATE()
Select GetDate()
--GETUTCDATE()
Select GETUTCDATE()
---ISDATE checks the format of date. If format is right than it return 1 otherwise 0
Select IsDate('14-03-02')-- Returns 0 as date format is wrong
Select SYSDATETIME()
Select IsDate(CURRENT_TIMESTAMP) --Returns 1 as date format provided by Current_TImeStamp is right
---- MONTH
Select MONTH(current_timestamp)
Select year(CURRENT_TIMESTAMP)
--SmallDateTimeFromParts
Select SMALLDATETIMEFROMPARTS(2014,07,29,1,04)
--SWITCHOFFSET
--- SYSDATETIME returnes system time stamp
Select SysDateTime()
-- SYSDATETIMEOFFSET
-- SYSUTCDATETIME
-- TIMEFROMPARTS
-- TODATETIMEOFFSET
----TSQL System Functions
---
select @@CONNECTIONS,getdate();
--@@Error to knowif error any came
Use Ms2012;
Go
Select * from db_owner.gender;
Update db_owner.Gender set Gender='UnKnown' where Gender_id=3;
delete from db_owner.gender where Gender_id=4;
if @@ERROR <> 0 Print N'There is no Gender Id 4'
Select * from db_owner.gender;
GO
-- @@IDENTITY to know last value IDENTITY value inserted
-- @@ROWCOUNT to see number of rows effected by a T-Sql Statement
use MS2012;
go
Update db_owner.gender set Gender='Male' where Gender_id=1;
Update Db_owner.Gender set gender='Female' Where Gender_id=2;
Update Db_owner.Gender set gender='Unkown' Where Gender_id=3;
if @@ROWCOUNT<> 0
print Concat('The number of rows affected are ' , @@Rowcount);
if @@ROWCOUNT=0
Print Concat(@@ROWCOUNT, ' no row effected' );
Select * from db_owner.gender;
go
-- COALESCE equal to NVL function of Oracle
Alter Table Db_owner.person
alter column middle_name nvarchar(20) null
Select * from db_owner.person
Update db_owner.Person set Middle_name=null where Person_id=103
Select First_name,Coalesce(Middle_name,null,'UnKown') from db_owner.Person
--ERROR_LINE returns the error at particular line when using with Try and Catch block
USE model;
GO
BEGIN TRY
SELECT 8/0;
END TRY
BEGIN CATCH
SELECT ERROR_LINE() AS ErrorLine;
Select ERROR_MESSAGE () As ErrorMessage
Select ERROR_NUMBER () As ErrorNumber
Select ERROR_PROCEDURE() as Proce
Select ERROR_SEVERITY () as Sever
Select ERROR_STATE() as Stat
END CATCH;
GO
/* ERROR_MESSAGE
ERROR_NUMBER
ERROR_PROCEDURE
ERROR_SEVERITY
ERROR_STATE*/
---Host_Id
Select HOST_ID() as HostId
---HOST_NAME
Select Host_name() HostName
---IsNull
Select ISNULL(NUll,'Jai')
Select * from db_owner.person
select IsNull(Middle_name,'Kumar (replaced)'),Middle_name from db_owner.person
---ISNUMERIC either 1 or 0 if 1 than parameter is number
Select ISNUMERIC('a')
--- NULLIF checks if two expressions are same or not. If same than returns
--null otherwise value of first parameter
Select NullIf('a','a') col1,NullIf('a','b'),NullIf('jai','jai')
----Security Functions
--- CURRENT_USER if connect by windows authentication or sa than its show DBO.
Select Current_user as currentUser
Select ORIGINAL_LOGIN() as OrgLogin
--Session user shows the user of sesison. normally it s same as current user function.
Select SESSION_USER
--Shows the user at OS level connected to sql server
Select SYSTEM_USER
--User_Name tell the name of user at sql server level
Select USER_NAME()
TSQL Metadata Functions
--App_Name() gives the name of the applicaiton.In following example it gives 'Microsoft Sql Server Management Stuido - Query' output
Select APP_NAME ()
--DB_ID returns the number assigned to a database
Select DB_ID()
--DB_Name name of database
Select DB_NAME() DBNAMe
---Object_Definition gets the definition of an object
Select * from sys.objects
where name='PERSON'
select * from ms2012.db_owner.gender
Select OBJECT_DEFINITION(object_ID('ms2012.db_owner.gender'))
--Object_id to know the object id
Select Object_id('ms2012.db_owner.person')
--Ojbect Name to know the object name
Select OBJECT_NAME(437576597),Object_id('ms2012.db_owner.person')
Select OBJECT_SCHEMA_NAME(437576597,8)
Select SCHEMA_ID('db_owner')
Select SCHEMA_NAME(16384)
---TSQL Configuration Functions
Select @@LOCK_TIMEOUT as TimeOutOfLog
Select @@MAX_CONNECTIONS as MaxConn
Select @@SERVERNAME as SrvrNm
Select @@SERVICENAME as SrvcNm
select @@SPID as SPID
Tuesday 22 July 2014
Table Recovery
Table recovery in Oracle 10g
Many a times it happens that a developer or sometimes you as
a DBA, accidently drops a table and want to correct things by restoring it
back.
Oracle9i Database introduced the concept of a Flashback
Query option to retrieve data from a point in time in the past, but it can’t
flash back DDL operations such as dropping a table. The only recourse is to use
table space point-in-time recovery in a different database and then recreate
the table in the current database using export/import or some other method.
This procedure demands significant DBA effort as well as precious time, not to
mention the use of a different database for cloning
However Oracle 10g came with excellent feature table
recovery is as simple as that running few very simple commands.
We discuss this
feature in this blog:
SQL> Select banner from v$version ;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release
10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE
10.2.0.1.0 Production
TNS for Linux: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 – Production
SQL> select * from tab;
TNAME TABTYPE CLUSTERID
------------------------------ ------- ----------
T1 TABLE
TEST_NULL TABLE
SQL> Drop Table T1;
Table dropped.
SQL> select * from tab;
BIN$/sNVxevp5A/gQKjAEQAYwA==$0 TABLE
Notice! We used “Drop Table T1” statement and
expected that table is dropped and spaced is freed. But this is not so. Instead
a new table has come with some bizarre name. This is the name that Oracle gave
to our table T1.
What happened is Oracle tossed a new terminology
called RECYCLEBIN just like the recycle bin that we have in our Windows
machines. Instead of dropping table and freeing space, Oracle kept table in
Recyclebin for just in case DBA wants to flashback it.
Let’s see what else RECYCLEBIN has stored there.
SQL> show recyclebin
ORIGINAL NAME
RECYCLEBIN NAME
OBJECT TYPE DROP TIME
---------------- --------------------------------------------
------------ -----------------------------------------
CURRENCY_TEST
BIN$/mGWpLuT4DLgQKjAEQAWBg==$0 TABLE 2014-07-17:16:46:32
CURRENCY_TEST
BIN$/mGWpLuS4DLgQKjAEQAWBg==$0 TABLE 2014-07-17:16:33:19
T1 BIN$/sNVxevp5A/gQKjAEQAYwA==$0 TABLE 2014-07-22:12:24:08
See! Except others I have my T1 table stored in
there. Now lets see the magic.
SQL> Flashback table t1 to before drop;
Flashback complete.
SQL> select * from tab;
TNAME TABTYPE CLUSTERID
------------------------------ ------- ----------
T1 TABLE
See. We got over table back at place. J
Now one important question arises how I can drop
my table completely if at all we want to drop it. In this case use PURGE option
of drop table.
SQL> Drop Table T1 Purge;
Table dropped.
SQL> show recyclebin
ORIGINAL NAME
RECYCLEBIN NAME OBJECT TYPE DROP TIME
---------------- ------------------------------
-------------------------------------------------- -------------------
CURRENCY_TEST
BIN$/mGWpLuT4DLgQKjAEQAWBg==$0 TABLE 2014-07-17:16:46:32
CURRENCY_TEST
BIN$/mGWpLuS4DLgQKjAEQAWBg==$0 TABLE 2014-07-17:16:33:19
This time, We did not get table listed in
RECYCLEBIN
This particular operation related to PURGE can be done in another way.
Once we drop the Table without PURGE clause we can use PURGE Clause as follows
to remove table from RECYCLEBIN.
SQL> Purge table t1;
Table purged.
Sometimes it happens that you dropped lots of
tables from one particular tablespace. So instead of doing PURGE one by one,
you can use following command simply to remove all entries in one go.
In this example, I had all of my tables in USERTBS
tablespace. So I used following command to remove all tables from RECYCLEBIN.
SQL> Purge Tablespace USERTBS;
Tablespace purged.
Similarly, If you had dropped tables related to
one particular user than you can use variant of this particular command.
SQL> Purge Tablespace UserTBS user test;
Tablespace purged.
OR
Connect to TEST user and run following command.
SQL> Purge Recyclebin;
Recyclebin purged.
You as DBA can use following command to remove
list of tables related to every tablespace.
SQL> Purge DBA_RECYCLEBIN;
This is not all. Using Flashback Table <> to
Drop we can flashback table to particular time or a scn.
FLASHBACK TABLE T1 TO
SCN 285954520;
Renaming is also possible.
FLASHBACK TABLE TEST TO
BEFORE DROP RENAME TO TEST2;
FLASHBACK TABLE TEST TO BEFORE DROP RENAME TO
TEST1;
This feature has definitely saved us from lots of
trouble in situation like this.
Any comment, suggestion would be appreciated.
Sunday 20 July 2014
Microsoft Sql Server tables and constraints Part 2
This is my third blog about Microsoft Sql Server database administration. In last blog we talked about keys in Sql Server and found that there is no difference between syntax's of defining these keys in Oracle and Sql Server.
In this blog we will discuss auto generation of key values. Just like Synonym of Oracle database. I have demonstrated this by doing T-Sql script. and you can also achive this using Studio as well.
Comments added in between each step would help you to understand concept easily.
First I have created IDNTY_TAB2 table in SAMPLE Database using SAMPLE schema and defined ID as Primary key and set it to a IDENTITY column
USE [Sample]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [sample].[Idnty_Tab2](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Nm] [nchar](50) NOT NULL
) ON [PRIMARY]
GO
Now! I have inserted following rows in the table. Notice that I have not provided value of ID primary Key column. As this column is IDENTITY column. So its generating values its own starting from 1.
Insert into idnty_tab2 values ('James')
Insert into idnty_tab2 values ('Davis')
Insert into idnty_tab2 values ('Smith')
Insert into idnty_tab2 values ('Samantha')
Insert into idnty_tab2 values ('Nancy')
Insert into idnty_tab2 values ('Deran')
Select and confirm that you get to see all the rows.
Select * from idnty_tab2
Now! Delete the row and query again to see the result
Delete from Idnty_tab2 where id=3
Select * from idnty_tab2
Now try to insert new row and query the table and see the value of ID column
Insert into idnty_tab2 values ('Smith')
Select * from idnty_tab2
You will notice that I has not used missing 3 as the value of ID. So to use deleted ID value 3 we need to set
IDENTITY_INSERT on table..Following statement would set this parameter ON.
Set Identity_Insert Idnty_Tab2 On;
After setting this Parameter we need to provide columns name as well. without column name INSERT statement would fail.
Insert into idnty_tab2 values ('Harris'); --Would Fail with following message.
--Msg 545, Level 16, State 1, Line 2
--Explicit value must be specified for identity column in table 'Idnty_Tab2' either when
--IDENTITY_INSERT is set to ON or when a replication user is inserting into a NOT FOR REPLICATION identity column.
Following statement would be successfull.
Insert into idnty_tab2 (id,nm) values (3,'Harris')
Confirm it once again
Select * from idnty_tab2 order by 1
Once you have inserted the missing values you should take this parameter OFF using follwoing parameter.
Set Identity_Insert Idnty_tab2 off;
Now start inserting the values again.
Insert into idnty_tab2 values ('James')
Select * from idnty_tab2 order by 1
Suppose we delete all the rows and again insert it.After insert when we query table and get to know that
instead from 1 ID is started from the higest value we had before we deleted all the rows. Sql Server instead of setting to 1 have started it from that value.
Delete from Idnty_Tab2
Insert into idnty_tab2 values ('James')
Select * from idnty_tab2 order by 1
Now to restart the feed from start we need to reset the seed by using following procedure
dbcc checkident('idnty_tab2',reseed,0)
Checking identity information: current identity value '9', current column value '0'.
DBCC execution completed. If DBCC printed error messages, contact your system administrator.
After using above procedure we insert values again and get to see that this time Sql Server has used 1 as starting value
Insert into idnty_tab2 values ('James')
Insert into idnty_tab2 values ('Davis')
Insert into idnty_tab2 values ('Smith')
Insert into idnty_tab2 values ('Samantha')
Insert into idnty_tab2 values ('Nancy')
Insert into idnty_tab2 values ('Deran')
Select * from idnty_tab2 order by 1
This is the behavior when we use DELETE statement, However if we use TRUNCATE statement than the counter is automatically set to its starting value 1; Lets use Truncate statement and see what happens
Truncate table Idnty_Tab2;
Select * from idnty_tab2 order by 1
Insert into idnty_tab2 values ('James')
Insert into idnty_tab2 values ('Davis')
Insert into idnty_tab2 values ('Smith')
Insert into idnty_tab2 values ('Samantha')
Insert into idnty_tab2 values ('Nancy')
Insert into idnty_tab2 values ('Deran')
Select * from idnty_tab2 order by 1
Using TRUNCATE command we have no need to reset the counter. It happens with DELETE Statement only
I hope this would clear any doubt.
If have any doubt please write back to me.Any suggestion/comments would be appriciated.
Thanks
Friday 11 July 2014
Microsoft Sql Server table and constraints Part 1
This is first part of a series of blog discussing tables,constraints in Microsoft Sql Server database. I have
created on database to store person information. For this I have used MSS 2008R2 version.
Drop table sample.gender
Create table sample.gender
(
id int primary key,
gender nvarchar(10) not null
)
Insert into Sample.gender values (1,'Male')
Insert into Sample.gender values (2,'Female')
Insert into sample.gender values (3,'Not Sure')
select * from sample.Gender
Drop table sample.person
Create table sample.person
(
id int primary key,
Name nvarchar(30) Not null,
LastName nvarchar(30) Not null,
Email nvarchar(15) not null,
Nationality nvarchar(20) not null,
gender int not null
)
Alter table sample.person add constraint fk_con foreign key (gender) references sample.gender (id)
truncate table sample.person
Insert into sample.person values (1,'Jai','Sharma','vat@gmail.com','Indian',1)
Insert into sample.person values (2,'Ram','Jain','RJ@gmail.com','Srilankan',1)
Insert into sample.person values (3,'Hariharn','Dev','hd@gmail.com','Singapore',1)
Insert into sample.person values (4,'Anmol','Sethi','AS@gmail.com','Indian',1)
Insert into sample.person values (5,'Rajan','Chawala','RC@gmail.com','Srilankan',1)
Insert into sample.person values (6,'Anamika','Mukharji','AM@gmail.com','Bangladesh',2)
Insert into sample.person values (7,'Rupali','Sen','RS@gmail.com','Aussie',2)
Insert into sample.person(id,name,lastname,email,nationality) values (8,'Radhika','Reddy','RR@gmail.com','Aussie')
select * from sample.person
--Adding a default constraint
Alter table Sample.Person
add constraint dflt_tblPerson_gender default 3 for gender
---Adding an column in table
Alter table sample.person
add city nvarchar(20)
constraint dflt_person_city default 'Melbourne'
---Drop a column from table
Alter table sample.person
drop column city
----Constraint cascade
---Check constraint
Alter table sample.person
add constraint chk_person_aga check (age > 0 and age <100)
Any comment,suggestions or correction is welcome.
created on database to store person information. For this I have used MSS 2008R2 version.
Drop table sample.gender
Create table sample.gender
(
id int primary key,
gender nvarchar(10) not null
)
Insert into Sample.gender values (1,'Male')
Insert into Sample.gender values (2,'Female')
Insert into sample.gender values (3,'Not Sure')
select * from sample.Gender
Drop table sample.person
Create table sample.person
(
id int primary key,
Name nvarchar(30) Not null,
LastName nvarchar(30) Not null,
Email nvarchar(15) not null,
Nationality nvarchar(20) not null,
gender int not null
)
Alter table sample.person add constraint fk_con foreign key (gender) references sample.gender (id)
truncate table sample.person
Insert into sample.person values (1,'Jai','Sharma','vat@gmail.com','Indian',1)
Insert into sample.person values (2,'Ram','Jain','RJ@gmail.com','Srilankan',1)
Insert into sample.person values (3,'Hariharn','Dev','hd@gmail.com','Singapore',1)
Insert into sample.person values (4,'Anmol','Sethi','AS@gmail.com','Indian',1)
Insert into sample.person values (5,'Rajan','Chawala','RC@gmail.com','Srilankan',1)
Insert into sample.person values (6,'Anamika','Mukharji','AM@gmail.com','Bangladesh',2)
Insert into sample.person values (7,'Rupali','Sen','RS@gmail.com','Aussie',2)
Insert into sample.person(id,name,lastname,email,nationality) values (8,'Radhika','Reddy','RR@gmail.com','Aussie')
select * from sample.person
--Adding a default constraint
Alter table Sample.Person
add constraint dflt_tblPerson_gender default 3 for gender
---Adding an column in table
Alter table sample.person
add city nvarchar(20)
constraint dflt_person_city default 'Melbourne'
---Drop a column from table
Alter table sample.person
drop column city
----Constraint cascade
---Check constraint
Alter table sample.person
add constraint chk_person_aga check (age > 0 and age <100)
Any comment,suggestions or correction is welcome.
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