What is SQL?

There are probably a hundred valid answers to this question.  Nonetheless; I run into the question fairly regularly and also see some rather inaccurate beliefs about it.  Let’s define some terms, I’ve attempted to order them in an order that helps with understanding.

“RDBMS” is an acronym for Relational Database Management System.

“SQL Server” is the RDBMS from Microsoft.  It has been around for many years and is a very mature product. It runs on a Windows Server and includes management tools and a great deal of functionality. Major versions have included MS SQL Server 6.5, SQL Server 7, SQL Server 2000, SQL Server 2005, SQL Server 2008, and SQL Server 2008 R2.

“MySQL” is another RDBMS server product. It is mostly open source and runs on a variety of platforms. 

“Oracle” is another RDBMS server product from the Oracle Corporation.

“Database” is a collection of digital data organized in a logic fashion (structure or schema). Depending on the RDBMS, this data can be spread across many files and/or disks.

“SQL” is an acronym for Structured Query Language. It is a declarative computer programming language used to work with data in a relational database (RDBMS).  This means that by itself, SQL is pretty generic. The language supports CRUD operations (Create, Read, Update, Delete) as well as schema creation and modification.

“T-SQL” is Transact-SQL and is the specific language used by the Microsoft SQL Server product. It had it’s beginnings in SQL but has been expanded to include procedural programming, variables, and many string/date/math/etc… functions.

“SQL Statement” generally this is used to mean a single “command” written in the SQL or T-SQL language.  Many statements are usually grouped together in a function and/or stored procedure. An example would be:

        SELECT * FROM TABLE

Some of the uses of SQL that are imprecise:
“The SQL Server power supply failed.”  The SQL Server is a service on a Windows Server and does not have a power supply, the host machine does though.

“The SQL database is large.”  This is mixing a language and a collection of data.