Database is similar to a data file in that it is a storage place for data. Like a data file, a database does not present information directly to a user; the user runs an application which accesses data from the database and which presents it to the user in an understandable format. Database systems are more powerful than data files in that data is more highly organized. In a well-designed database, there are no duplicate data that the user or application would need to update at the same time. Related pieces of data are grouped together in a single structure or record, and relationships can be defined between these structures and records. When working with data files, an application must be coded to work with the specific structure of each data file. In contrast, a database contains a catalog that applications use to determine how data is organized. Generic database applications can use the catalog to present users with data from different databases dynamically, without being tied to a specific data format. A database typically has two main parts: first, the files holding the physical database and second, the database management system (DBMS) software that applications use to access data. The DBMS is responsible for enforcing the database structure including: Maintaining relationships between data in the database. Ensuring that data is stored correctly and that the rules defining data relationships are not violate. Recovering all data to a point of known consistency in case of system failures. Structured Query Language To work with data in a database, you have to use a set of commands and statements (language) defined by the DBMS software. Several different languages can be used with relational databases; the most common is SQL. The American National Standards Institute (ANSI) and the International Standards Organization (OSI) define software standards, including standards for the SQL language. SQL Server 2008 supports the Entry Level of SQL-92, the SQL standard published by ANSI and ISO in 1992. The dialect of SQL supported by Microsoft SQL Server is called Transact- SQL (T-SQL). T-SQL is the primary language used by Microsoft SQL Server applications.