Software Applications Programming Errors and solutions.

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.

Clustered index which reordered the table and saved separately as index table(data pages stored as B-tree) there can be one clustered index per db & Non clustered index is typically a index(data pages stored as heap) A table can have only one clustered index with many non clustered indexes. The leaf nodes of the cluster index stores data pages and non clustered index stores key values(where as table includes clustered index) or rid's(table contains non cluster index only).