Software Applications Programming Errors and solutions.

A covering index is a non-clustered index which includes all columns referenced in the query and therefore, the optimizer does not have to perform an additional look-up to the table in order to retrieve the data requested. As the data requested is all indexed by the covering index, it is a faster operation. covering index is a non-clustered index which stores additional columns at leaf level to avoid bookmark lookup to heap/clustered index.this is typically created using INCLUDE clause. Let say we have a table tab1 and we have columns starts from column 1 to 10. and we have clustered index on column1 and non clustered index on column 2 . for example you written a query select * from tab1 where column 2=200. this query first will go and look for the matching data in non clustered index and because of our query want to retrieve all the columns it will perform key look up , not helathy. this time i had one more non clustered index on column3 a...

SQL server assign default port 1433 to default instance...for named instance it dynamically allots a port number, ideally it is five digit port number. To see port of SQL Server you can check as below. Go to configuration manager-->SQL Serve network Configuration-> Select instance-->right click TCP/IP properties-->IP Properties

Dac means dedicared admin account, which is used to access sql server at .by default 1433 is sql server port , 1434 ia dac account. Starting the server in single user mode will use DAC (Dedicated Administrative Connection) connection. DAC Connection will use If the number of connections are limited for the instance and all are connected and if some one wants to connect and fails to troubleshoot if DBA want to connect he will also be restricted then he can use DAC connection to connect to the instance. When ever the SQL Server standard connection not establish the connection then we go with DAC connection . only sys admin can use this DAC to connect the server and troubleshoot the problems.

1.What are Differences in Delete & Truncate . 2.What are Differences in UNIQUE and Primary key ? 3. What are the agents involved in replication 4.Which Types of clusters and how many ips are required to install failover cluster? 5.Configuration of logshipping and DB mirroring. 5.What are Types of backups and backup scenario? 6.What is deadlock and blocking? 7.Differences between clustered and non clustered indexes? 8.Why SQL Server Agent is used? 9.What are Types of System databases 10.What are the steps for restoring a database?

Linked server means to retrieve the data from the other server to connect our own instance, before configure the linked server we must know the target server login and password then only we access the data from the other server. Linked server means access the data from one server another server is called linked server. store procedure is sp_addlinkedserver. When we have to run the distributed transactions we need to linkup the servers internally we use linked servers concept.Here distributed transactions means A query which has to executed on multiple servers at a time is called distributed transactions.

Checkpoint : Write all the dirty pages into buffer cache. It is not clear from buffer cache is called checkpoint.check point is the internal process which will take dirty blocks from buffer pool to data file on interval based. Lazywriter: Write all the dirty pages into buffer cache. It is clear from buffer cache is called lazywriter Checkpoint and lazywrite do the same job of flushing out the (8k size) pages from the memory to disk the only difference is of when they do this task. A lazy write does its task when there is resource contention and sql engine needs to process more pages and bring them in the memory. The lazy writer in this case gets all the pages which have been residing in the memory for the longest time and flushes them to the disk. A checkpoint on the other hand does the task for the SQL engine to create a stable point from which SQL can recover in case there is a failure of service during some processing. A checkpoint is not issued due to lack of resources. Please not...

Grant/Revoke are the keywords which uses to grant/revoke privileges on an object to/from a user/group. Grant is a keyword you use when you want to authorize/authenticate. a principal and Revoke is the Keyword used when you want to take back the Authorization/authentication from the Principal. Principal refers to Lo-gin at instance level.Database user at Database level. Grant,revoke,deny,with grant are object level security.Grant means giving permission on a particular object to user.Command: grant privilege on object name to username. Revoke means taking back the permission. Command: revoke privilege on object name from username. Deny means restrict user not to do something command: deny privilege on object name to username. With grant means by using grant user can give grant permission to other user command: grant privilege on object name to user with grant.