Sql server: Data: it’s a collection of facts and figures. Information: The data arranged in an order (ascending or descending). FMS: File Management System Database: This is used to maintain entire data in the form of tables. Different types of databases are there, they are as follows: DBMS: Database Management System, dbase, FoxBASE, Access-97 RDBMS: Relational Database Management System. Oracle, Sql Server, Informatica, OORDBMS: Object Oriented Relational Database Management System. Oracle 8i, 9i, 10g, sql server 2005, HRDBMS: Imsdb, db2. Sql server: Transaction sql DDL(Data Definition Language): create, Alter, and Drop This basically creates structure of a table, modifies or deletes structure of a table. DML(Data Manipluation Language): Insert, Update, Delete, Truncate This used to insert, modify, update, and delete the entire information in a table. DQL(Data Query Language): to retrieve the contents of a table Select Constraints: constraints are used to restrict invalid data. These are divided into two types; they are Table level Constraints, & Column level Constraints. Column level constraints are Not null: this will not allow empty values Unique: this will not allow duplicate data (allow values are different) Primary key: it’s a combination of unique and not null constraint; every table must contain only one primary key. Foreign key: it’s a combination of not null and the values can duplicate which reference is already to another table column whose constraint is primary key. Check: to specify range of values like salary range for an employee.