Error:

Msg 15137, Level 16, State 1, Procedure sp_xp_cmdshell_proxy_account, Line 1 [Batch Start Line 1]
An error occurred during the execution of sp_xp_cmdshell_proxy_account. Possible reasons: the provided account was invalid or the ‘##xp_cmdshell_proxy_account##’ credential could not be created. Error code: 5(Access is denied.), Error Status: 0.

Fix:

• Run SQL Server Management Studio as Administrator
• Validate and make sure password is correct

Alternatives:
Create a credential

USE [master]
GO
ALTER CREDENTIAL [##xp_cmdshell_proxy_account##] WITH IDENTITY = domainaccount', SECRET = N'password'
GO


Below are the steps that can be taken to make sure that you are seeing right numbers.

– Clear the cache by running the above Script provided in this Link
– Run the query that you are trying to performance tune and note the Statistics. (a)
– Run the above script again to clear the cache.
– Now execute the tuned query and note down the Statistics. (b)

Query Statistics (a) and (b) would now be comparable as both of them are executed over the clean cache.


CHECKPOINT;
GO
DBCC DROPCLEANBUFFERS
DBCC FREEPROCCACHE
DBCC FREESYSTEMCACHE ('ALL')
DBCC FREESESSIONCACHE
GO


Note that this script is solely for running on Development environments, do not run in Production as it would cause issues to queries that depend on cached data.

Mission Critical Performance
Deeper Insights Across Data
Hyper scale Cloud

Below is the link to the Data sheet.
SQL Server 2016 PDF data Sheet

Watch this video for more details.

More Info:
https://msdn.microsoft.com/en-us/library/Dn935011.aspx

[sql]
EXEC sp_cdc_change_job @job_type=’capture’,@maxtrans = ‘10000’,@retention=200
[/sql]

The above code gives the below error.

Msg 22995, Level 16, State 1, Procedure sp_cdc_change_job_internal, Line 39
A value for the parameter @retention cannot be specified when the job type is ‘capture’. Specify NULL for the parameter, or omit the parameter from the statement.

Resolution:

Remove @retention input parameter.

[sql]
EXEC sp_cdc_change_job @job_type=’capture’,@maxtrans = ‘10000’
[/sql]

The below code explains how to convert the data in a table to xml form and then convert the xml back into table data.

Creating sample table with data:

CREATE TABLE tmpEmployee(ID INT,NAME VARCHAR(100))
GO

INSERT INTO tmpEmployee
SELECT 1,'Devi'
union
SELECT 2,'Prasad'
GO


SELECT * FROM tmpEmployee
GO


Below code converts data and schema of table tmpEmployee into XML, Then it uses the XML to convert it back into the table:

/*Below code converts Table SCHEMA & Data to XML*/

DECLARE @TableData XML,@TableSchema XML

SELECT @TableSchema = (
select column_name,
data_type,
case(is_nullable)
when 'YES' then 'true'
else 'false'
end as is_nullable,
CHARACTER_MAXIMUM_LENGTH as Charlen
from information_schema.columns [column]
where table_name = 'tmpEmployee'
for xml auto,root('Table')
)

SELECT @TableData = (
SELECT *
FROM tmpEmployee Row
FOR XML AUTO, BINARY BASE64,root('TableData')
)

SELECT @TableSchema,@TableData

EXEC sp_executeSQl @SQL,N'@TableData xml',@TableData=@TableData


Output:

tmpEmployee:

ID NAME
----------- ----------------------------------------------------------------------------------------------------
1 Devi
2 Prasad


(2 row(s) affected)


@TableSchema:

<Table>
<column column_name="ID" data_type="int" is_nullable="true" />
<column column_name="NAME" data_type="varchar" is_nullable="true" Charlen="100" />
</Table>


@TableData:

<TableData>
<Row ID="1" NAME="Devi" />
<Row ID="2" NAME="Prasad" />
</TableData>


Table generated from XML:

ID NAME
----------- ----------------------------------------------------------------------------------------------------
1 Devi
2 Prasad


(2 row(s) affected)


Creating Sample Data:

--DROP TABLE tempForView
CREATE TABLE tempForView(
ID INT
);
GO

INSERT INTO tempForView
SELECT 1
UNION
SELECT 2
UNION
SELECT 3;
GO

Check Option:
Check option ensures that the modification of data in the view will come up in the view again.

Example:

CREATE VIEW vw_TempWithOutCheckOption
AS
SELECT * fROM tempForView WHERE ID > 0
GO

CREATE VIEW vw_TempWithCheckOption
AS
SELECT * fROM tempForView WHERE ID > 0
WITH CHECK OPTION;
GO

Lets try to inset/Update data in view vw_TempWithOutCheckOption.

UPDATE vw_TempWithOutCheckOption SET ID = -1 WHERE ID = 1
GO

INSERT INTO vw_TempWithOutCheckOption(ID)
SELECT -2
GO

SELECT * FROM vw_TempWithOutCheckOption
GO

The above query runs and the data will be inserted/Updated in the underlying table but will not come up in the view.

Now when we try to insert update data in the view vw_TempWithCheckOption

UPDATE vw_TempWithCheckOption SET ID = -2 WHERE ID = 2
GO

INSERT INTO vw_TempWithCheckOption(ID)
SELECT -3
GO

SELECT * FROM vw_TempWithCheckOption
GO

As we are trying to insert/Update data which would not be part of the view, we are getting the error:

Msg 550, Level 16, State 1, Line 2
The attempted insert or update failed because the target view either specifies WITH CHECK OPTION or spans a view that specifies WITH CHECK OPTION and one or more rows resulting from the operation did not qualify under the CHECK OPTION constraint.
The statement has been terminated.

Encryption:

Encryption can be used when you want to hide the definition of the View.

CREATE VIEW vw_TempWithEncryption
WITH ENCRYPTION
AS
SELECT * fROM tempForView WHERE ID > 0;
GO

CREATE VIEW vw_TempWithOutEncryption
AS
SELECT * fROM tempForView WHERE ID > 0;
GO


SELECT TEXT fROM sys.syscomments WHERE ID = OBJECT_ID('vw_TempWithEncryption')
SELECT TEXT fROM sys.syscomments WHERE ID = OBJECT_ID('vw_TempWithOutEncryption')

The definition of the view that is created with encryption is not present in sys.syscomments.

SchemaBinding:
When a view is created with schema binding then it does not allow DDL modifications to the underlying tables which affect the view definition.

CREATE VIEW vw_TempWWithSchemaBinding
WITH SCHEMABINDING
AS
SELECT ID fROM dbo.tempForView WHERE ID > 0;
GO

DROP TABLE dbo.tempForView

It does not allow to drop the table dbo.tempForView as the view is referencing it and it is created with SCHEMABINDING.

Msg 3729, Level 16, State 1, Line 1
Cannot DROP TABLE ‘dbo.tempForView’ because it is being referenced by object ‘vw_TempWWithSchemaBinding’.

VIEW_METADATA:
when the applications accessing SQL Server request browse-mode metadata SQLServer basically provides the details of the TABLES from which the columns in the views are built.
But when a view is created with this option then SQL Server does not provide the base tables of the columns in the view.

More info can be found in MSDN:
http://msdn.microsoft.com/en-us/library/ms187956.aspx