1).Definitions of database testing?
Database testing nothing but testing the database .it can be tested manually or automatically using tools.
2).What are the testing criteria in database testing?
In database testing we have to test following criteria like
a) Data validity testing: in validity testing we should known about SQL quires and how to use it.
b) Data integrity testing: in integrity testing we should known about integrity performance of database.
c) Data manipulation and performance testing: in that testing we have to know about data design table and data implementation.
d) Data triggering and functionality testing: in that testing we have to known about data triggering concepts and functionality of add, delete, update and modify concepts in database.
3).what are the SQL statement have you used in database testing?
In database testing we have to test two type of SQL statement such as
a) DDL (data definition language):
DDL is nothing but create database and create table.
Ex.1. Create database (database name) vel
2. Create table (table name) murugan (id int, name varchar (10), address varchar (10))
b) DML (Data manipulations language):
DML is nothing but delete, insert, update etc...
Ex.1.insert table values (1,’murugan’,’chennai’) ;
2. delete * from table name =’murugan’;
3. update table set name=’balaji’ from id=1;
4).what are the different stage involved in database testing?
Verify the data in database with respect to front end transactions.
Verify the constraint (primarykey, forignkey …)
Verify the performance of procedure
Verify the triggers (execution of triggers)
Verify the transactions (begin, commit, rollback)
Verify the table relationship (1-1, 1-meny, meny-meny)
5).what is a fast database retrieval rate in database?
A database retrieval rate is 5 micro sec.
6).why we go to database testing?
a) Database testing is primer.
b) It is back-end and front-end applications.
c) Testing the applications vs. testing the DBMS (Database Management System)
d) Knowledge requirements for database testing.
e) Data must pass quality assurance too.
7) What are the common problem arising in database?
a). Relational database that affect the database applications.
b). improperly normalized database (first, 2nd, 3rdnarmalizations).
Common for database:
· Database size ~15 terabytes (this is total for all database)
2. What is a Stored Procedure? - Its nothing but a set of T-SQL statements combined to perform a single task of several tasks. It’s basically like a Macro so when you invoke the Stored procedure, you actually run a set of statements.
3. Can you give an example of Stored Procedure? - sp_helpdb, sp_who2, sp_renamedb are a set of system defined stored procedures. We can also have user defined stored procedures which can be called in similar way.
4. What is a trigger? - Triggers are basically used to implement business rules. Triggers is also similar to stored procedures. The difference is that it can be activated when data is added or edited or deleted from a table in a database.
5. What is a view? - If we have several tables in a db and we want to view only specific columns from specific tables we can go for views. It would also suffice the needs of security some times allowing specific users to see only specific columns based on the permission that we can configure on the view. Views also reduce the effort that is required for writing queries to access specific columns every time.
6. What is an Index? - When queries are run against a db, an index on that db basically helps in the way the data is sorted to process the query for faster and data retrievals are much faster when we have an index.
7. What are the types of indexes available with SQL Server? - There are basically two types of indexes that we use with the SQL Server. Clustered and the Non-Clustered.
8. What is the basic difference between clustered and a non-clustered index? - The difference is that, Clustered index is unique for any given table and we can have only one clustered index on a table. The leaf level of a clustered index is the actual data and the data is resorted in case of clustered index. Whereas in case of non-clustered index the leaf level is actually a pointer to the data in rows so we can have as many non-clustered indexes as we can on the db.
9. What are cursors? - Well cursors help us to do an operation on a set of data that we retrieve by commands such as Select columns from table. For example : If we have duplicate records in a table we can remove it by declaring a cursor which would check the records during retrieval one by one and remove rows which have duplicate values.
10. When do we use the UPDATE_STATISTICS command? - This command is basically used when we do a large processing of data. If we do a large amount of deletions any modification or Bulk Copy into the tables, we need to basically update the indexes to take these changes into account. UPDATE_STATISTICS updates the indexes on these tables accordingly.
11. Which TCP/IP port does SQL Server run on? - SQL Server runs on port 1433 but we can also change it for better security.
12. From where can you change the default port? - From the Network Utility TCP/IP properties –> Port number. Both on client and the server.
13. Can you tell me the difference between DELETE & TRUNCATE commands? - Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.
14. Can we use truncate command on a table which is referenced by FOREIGN KEY? - No. We cannot use truncate command on a table with Foreign Key because of referential integrity.
15. What is the use of DBCC commands? - DBCC stands for database consistency checker. We use these commands to check the consistency of the databases, i.e., maintenance, validation task and status checks.
16. Can you give me some DBCC command options? (Database consistency check) - DBCC CHECKDB - Ensures that tables in the db and the indexes are correctly linked. and DBCC CHECKALLOC - To check that all pages in a db are correctly allocated. DBCC SQLPERF - It gives report on current usage of transaction log in percentage. DBCC CHECKFILEGROUP - Checks all tables file group for any damage.
17. What command do we use to rename a db? - sp_renamedb ‘old name’, ‘new name’
18. Well sometimes sp_reanmedb may not work you know because if some one is using the db it will not accept this command so what do you think you can do in such cases? - In such cases we can first bring to db to single user using sp_dboptions and then we can rename that db and then we can rerun the sp_dboptions command to remove the single user mode.
19. What is the difference between a HAVING CLAUSE and a WHERE CLAUSE? - Having Clause is basically used only with the GROUP BY function in a query. WHERE Clause is applied to each row before they are part of the GROUP BY function in a query.
20. What do you mean by COLLATION? - Collation is basically the sort order. There are three types of sort order Dictionary case sensitive, Dictionary - case insensitive and binary.
21. What is a Join in SQL Server? - Join actually puts data from two or more tables into a single result set.
22. Can you explain the types of Joins that we can have with Sql Server? - There are three types of joins: Inner Join, Outer Join, Cross Join
23. When do you use SQL Profiler? - SQL Profiler utility allows us to basically track connections to the SQL Server and also determine activities such as which SQL Scripts are running, failed jobs etc..
24. What is a Linked Server? - Linked Servers is a concept in SQL Server by which we can add other SQL Server to a Group and query both the SQL Server dbs using T-SQL Statements.
25. Can you link only other SQL Servers or any database servers such as Oracle? - We can link any server provided we have the OLE-DB provider from Microsoft to allow a link. For Oracle we have an OLE-DB provider for oracle that Microsoft provides to add it as a linked server to the sql server group.
26. Which stored procedure will you be running to add a linked server? - sp_addlinkedserver, sp_addlinkedsrvlogin
27. What are the OS services that the SQL Server installation adds? - MS SQL SERVER SERVICE, SQL AGENT SERVICE, DTC (Distribution transact co-ordinate)
28. Can you explain the role of each service? - SQL SERVER - is for running the databases SQL AGENT - is for automation such as Jobs, DB Maintenance, and Backups DTC - Is for linking and connecting to other SQL Servers
29. How do you troubleshoot SQL Server if it’s running very slow? - First check the processor and memory usage to see that processor is not above 80% utilization and memory not above 40-45% utilization then check the disk utilization using Performance Monitor, Secondly, use SQL Profiler to check for the users and current SQL activities and jobs running which might be a problem. Third would be to run UPDATE_STATISTICS command to update the indexes
30. Let’s say due to N/W or Security issues client is not able to connect to server or vice versa. How do you troubleshoot? - First I will look to ensure that port settings are proper on server and client Network utility for connections. ODBC is properly configured at client end for connection ——Make pipe & read pipe are utilities to check for connection. Make pipe is run on Server and read pipe on client to check for any connection issues.
31. What are the authentication modes in SQL Server? - Windows mode and mixed mode (SQL & Windows).
32. Where do you think the user’s names and passwords will be stored in sql server? - They get stored in master db in the sysxlogins table.
33. What is log shipping? Can we do log shipping with SQL Server 7.0 - Log shipping is a new feature of SQL Server 2000. We should have two SQL Server - Enterprise Editions. From Enterprise Manager we can configure the log shipping. In log shipping the transactional log file from one server is automatically updated into the backup database on the other server. If one server fails, the other server will have the same db and we can use this as the DR (disaster recovery) plan.
34. Let us say the SQL Server crashed and you are rebuilding the databases including the master database what procedure to you follow? - For restoring the master db we have to stop the SQL Server first and then from command line we can type SQLSERVER .m which will basically bring it into the maintenance mode after which we can restore the master db.
35. Let us say master db itself has no backup. Now you have to rebuild the db so what kind of action do you take? - (I am not sure- but I think we have a command to do it).
36. What is BCP? When do we use it? - Bulk Copy is a tool used to copy huge amount of data from tables and views. But it won’t copy the structures of the same.
37. What should we do to copy the tables, schema and views from one SQL Server to another? - We have to write some DTS packages for it.
38.What is difference between inner and outer join?
Inner join: displays only matching record from 2 tables
Outer join:
Left outer join display all the records from 1st table even
if dont have matching record in 2nd table
rignt outer join display all the record from the 2nd table
even if there is not matching record in 1st table
39.Difference between delete and truncate?
TRUNCATE
1. It is DDL.
2. Speed is faster
3. Do not Check Constraints.
4. Roll back is not possible.it will delete the structure of the table.
5. Cannot use where clause
DELETE
1. It is not a DDL
2. Speed is slow
3. Check constraints, If Exists then shoe error.
4. We can rollback.
5. User Where Clause
40.How to find least 10 salaries from salary table?
