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A relational database (RDB[1]) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. [2] A database management system used to maintain relational databases is a relational database management system (RDBMS). Many relational database systems are equipped with the option of using SQL (Structured Query Language ...
Database. An SQL select statement and its result. In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS additionally encompasses the ...
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 ...
PostgreSQL supports a binary communication protocol that allows applications to connect to the database server. The protocol is versioned (currently 3.0, as of PostgreSQL 7.4) and has a detailed specification. [47] The official client implementation of this communication protocol is a C API, libpq. [48]
SQLite (/ ˌ ɛ s ˌ k juː ˌ ɛ l ˈ aɪ t /, [4] [5] / ˈ s iː k w ə ˌ l aɪ t / [6]) is a database engine written in the C programming language.It is not a standalone app; rather, it is a library that software developers embed in their apps.
In the fields of databases and transaction processing (transaction management), a schedule (or history) of a system is an abstract model to describe the order of executions in a set of transactions running in the system. Often it is a list of operations (actions) ordered by time, performed by a set of transactions that are executed together in ...
Cardinality (data modeling) Within data modelling, cardinality is the numerical relationship between rows of one table and rows in another. Common cardinalities include one-to-one, one-to-many, and many-to-many. Cardinality can be used to define data models as well as analyze entities within datasets.
Hierarchical database model. A hierarchical database model is a data model in which the data are organized into a tree -like structure. The data are stored as records which are connected to one another through links. A record is a collection of fields, with each field containing only one value. The type of a record defines which fields the ...