SQL

Computers keep lots of facts in big lists. We use a special way to talk to them. This is called SQL. It helps us find what we need fast.

One person can use one command to find many things. This makes work very quick. It also helps us change or add new facts.

People first made this in the 1970s. It was made at a place called IBM. It was even called SEQUEL at first.

Now, many computers use this way to talk. It is a standard for the whole world. It helps keep data safe and neat.

SQL is a very useful tool for computers.

Computers store lots of facts in big lists. We call these lists databases. To talk to these databases, we use a language called SQL. SQL stands for Structured Query Language. It helps us manage and find data easily.

In the 1970s, people at IBM made SQL. Two men named Donald Chamberlin and Raymond Boyce led the work. They first called it SEQUEL. Later, they changed the name to SQL. This was because SEQUEL was already a trademark for another company.

SQL is very helpful. In the past, finding data was hard. With SQL, one single command can find many records at once. You do not even have to tell the computer how to find them. You just ask for what you want.

SQL became a global standard in the 1980s. This means many different computer systems agree to use it. However, not every system follows the rules perfectly. Because of this, code often needs small changes to work on a new system. There are many new versions of the SQL standard today.

Computers use databases to store huge amounts of information. To talk to these databases, people use a special language called SQL. SQL stands for Structured Query Language. It is a tool used to manage data in a relational database management system. This is a way to organize information that has clear relations between different things. SQL is very important because it helps us handle structured data with ease.

SQL works in a very clever way. It is a declarative language, which means you tell the computer what you want rather than how to get it. In the past, people had to give many specific steps to find one piece of data. With SQL, you can use one single command to access many different records at once. You do not have to tell the computer exactly how to reach a specific record. This makes the work much faster and simpler for humans.

This language has a long history that began in the 1970s. Two men named Donald D. Chamberlin and Raymond F. Boyce developed it at IBM. They first called the language SEQUEL, which stood for Structured English Query Language. They later changed the name to SQL because SEQUEL was a trademark of another company. They built it to work with a system called System R. This was based on a famous idea from a man named Edgar F. Codd.

SQL has become a global standard for many years. The American National Standards Institute named it a standard in 1986. The International Organization for Standardization did the same in 1987. There have been many new versions of the standard over time. These include updates in 1989, 1992, 1999, and 2003, among many others. The most recent major update was in 2023. These updates add new features like ways to handle JSON data.

Even though there are rules, not every system uses them the same way. Most SQL code needs small changes before it can move to a different database. This is because different companies make their own versions of the language. Some systems might handle dates or times differently than others. Some might even use different rules for capital letters in names. This means that while SQL is a shared language, every computer speaks it with a slightly different accent.

Structured Query Language, or SQL, is a domain-specific language. It is used to manage data within a relational database management system (RDBMS). This type of system organizes information into structured formats. It uses relations between different entities and variables to keep data orderly. SQL is essential because it allows users to interact with complex data sets efficiently. It serves as the primary bridge between human instructions and digital data storage.

SQL functions as a declarative language. This means a user describes what they want to achieve rather than how to do it. In older systems, programmers had to write complex steps to find specific data. SQL changed this by allowing one command to access many records at once. It also removes the need to specify how to reach a record physically. The system decides whether to use an index or another method to find the data. This process makes data retrieval much faster and more intuitive for developers.

The language is divided into several functional classes of statements. The Data Query Language (DQL) is used to retrieve specific information. Data Manipulation Language (DML) allows users to insert, update, or delete data. Data Definition Language (DDL) is used for creating and modifying the database schema. Finally, Data Control Language (DCL) handles data access control and security. Each class performs a distinct role in managing the life cycle of data.

SQL has a rich history rooted in mathematical theory. It was based on relational algebra and tuple relational calculus. In 1970, Edgar F. Codd published an influential paper on the relational model. This paper described a way to manage large shared data banks. Following this, Donald D. Chamberlin and Raymond F. Boyce developed SQL at IBM. They initially called it SEQUEL, or Structured English Query Language. They later dropped the vowels to create the name SQL. This change was necessary because "SEQUEL" was a trademark of another company.

IBM's early work led to several important commercial products. They developed System R as a prototype in the 1970s. This led to the release of System/38, SQL/DS, and IBM Db2. These products became available between 1979 and 1983. Relational Software, now known as Oracle Corporation, also developed SQL-based systems. They released Oracle V2 for VAX computers in June 1979. These early successes helped SQL become the dominant language for databases.

SQL is now a recognized global standard. The American National Standards Institute (ANSI) adopted it in 1986. The International Organization for Standardization (ISO) followed in 1987. The standard has been revised many times to add new features. Major updates occurred in 1989, 1992, 1999, 2003, 2006, 2008, 2011, 2016, and 2023. The 2023 update added support for JSON data and Property Graph Queries. These revisions ensure the language evolves with new technology.

Despite these standards, most implementations are not fully compatible. This lack of portability means code often needs changes to work on different systems. For example, PostgreSQL handles unquoted names differently than the SQL standard. The standard says names should be upper case, but PostgreSQL uses lower case. Other vendors might use different syntax for dates, times, or string concatenation. This happens because the standard is massive and complex. Many companies also prioritize performance or backward compatibility over strict adherence to the rules.