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SQL is structured query language, which is used in various data bases such as MySQL, DB2, Oracle, Access. Microsoft SQL server, is a language specific to Microsoft database. So, one can say that SQL is used in various database. There is some specific function in both ORACLE and Microsoft SQLthat perform the same function, E.g. ISNULL, in Microsoft sequel server and NVL in Oracle perform the same function.
Today we are going to learn about:
- Type of database
- file server
- file system
- client server
- Working with SQL server
- Types of SQL statement in Microsoft SQL server.
Type of database
You have worked with MS- Access, MS- Excel or text files, these are a kind of databases. Local files are located in our system and any change made to the data in these files is not going to reflect in other copy or same file with other person until and unless you share that file with your friend. Consider an example, suppose you have shared a same file which you have with you with your friend, then the change which you made in your file will not be reflected in your friend’s file, so this kind of architecture is file server architecture, as they are located in your system and server is storage device. If we keep any file on server and provide access to and your friend, then both of you will be able to access that file and can make changes. So, Access, excel is a file server architecture and work on file based system.
SQL server is a client-server architecture, in which multiple people can access the data which is stored on server and depending upon the access right they can make changes to the data which will be reflected to everybody looking or logging into that data. This kind of performance is acceptable in LAN, but it suffers in case of WAN as the links are slow.
To remove this drawback, we move to server system/SQL server/ Server based data. In this server is a processing partner and a storage device and all the database stores on it. Client request will lead to processing on server and then the result is sent to client for formatting and display. Performance is much better in this but smaller amount of data is transmitted. Both client and server can do data processing.
How it works:
There are two, three or more OLE DB components, which are client or user system; used to access the data. Request is send to network server from client or user system; the network server sends the same request to database server and further that request goes to database.
Once the result is generated then from database it goes to Database server, then to network server and finally to computer from which a request is made.
Client server database, there is a single point of contact, security is there, online backup facility is there as compared to File server.