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SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
A relational database with no extensions, contains relations in the mathematical sense, i.e. A relation is a subset of the cross product of sets, thus a set. For efficiency reasons, those relations are indexed by keys. I don't remember the LIMIT clause, but in principle an SQL query may produce a bag as a result.
The SQL language is subdivided into several language elements, including: Keywords are words that are defined in the SQL language. They are either reserved (e.g. SELECT, COUNT and YEAR), or non-reserved (e.g. ASC, DOMAIN and KEY). List of SQL reserved words. Identifiers are names on database objects, like tables, columns and schemas. An ...
A query language, also known as data query language or database query language (DQL), is a computer language used to make queries in databases and information systems. In database systems, query languages rely on strict theory to retrieve information. [1] A well known example is the Structured Query Language (SQL).
Pronunciation may even vary within a single speaker's vocabulary, depending on narrow contexts. As an example, the database programming language SQL is usually said as three letters, but in reference to Microsoft's implementation is traditionally pronounced like the word sequel.
In SQL, the data manipulation language comprises the SQL-data change statements, [3] which modify stored data but not the schema or database objects. Manipulation of persistent database objects, e.g., tables or stored procedures, via the SQL schema statements, [3] rather than the data stored within them, is considered to be part of a separate data definition language (DDL).
Soundex is the most widely known of all phonetic algorithms (in part because it is a standard feature of popular database software such as IBM Db2, PostgreSQL, [2] MySQL, [3] SQLite, [4] Ingres, MS SQL Server, [5] Oracle, [6] ClickHouse, [7] Snowflake [8] and SAP ASE. [9]) Improvements to Soundex are the basis for many modern phonetic algorithms.
[6] [7] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [1] and "SQL", the acronym for Structured Query Language. A relational database organizes data into one or more data tables in which data may be related to each other; these relations help structure the data. SQL is a language that programmers use ...