1.data base testing is also called as back end end testing.we conduct this testing based on data validation and data integrity.data validation means that whether front end values are correctly storing into back tables content or not.data integrity means that whether impact of front end operations is working on back end tables content or not.

3.sdlc means soft ware development life cycle.it contains all the stages in development such as information gathering,analysis,design,coding,testing ,maintainence.

2.its a server ,what ever the web request user send it receives them and give response to that requests.

1.data base testing is also called as back end end testing.we conduct this testing based on data validation and data integrity.data validation means that whether front end values are correctly storing into back tables content or not.data integrity means that whether impact of front end operations.

2.web server:A web server is a computer which serves HTML pages to the clients requests i.e web browsers .

3.in product based company there is  no question of testing the product in development stage .the complete product would be developed and would be given for QA team for testing.so first comes the stage of development and then when te product is complete then testing and when all the requirements are achieved then the product would be given to the delivery team for release.

Data base testing is also called as back end Database testing is conducted to validate data in the database w.r.t front end DML transactions the DML operations are
Inserting Data into data base
Delecting the data from the database
Updateing the data in the database
During this testing the above are performed on the database or not

Web server means it is a server it recives requests from the client and process the data and give the response regarding the request the example is internet

the SDLC of any company depends on the organization the genral process of SDLC is
Business Requirements -----> system Requirements ----> Designing ----> Codeing -----> testing -----> Maintance