Table (database)

In a <a href="/facts/Database/VYcpkevb">database</a>, a table is a collection of related data organized in <a href="/facts/Table_(information)/vQcp2QSb">table format</a>; consisting of <a href="/facts/Column_(database)/WB91xSVs">columns</a> and <a href="/facts/Row_(database)/PIpv7c9e">rows</a>.
In <a href="/facts/Relational_database/pEKGmJLy">relational databases</a>, and <a href="/facts/Flat_file_database/aNeNVE3h">flat file databases</a>, a table is a set of data elements (values) using a model of vertical <a href="/facts/Column_(database)/WB91xSVs">columns</a> (identifiable by name) and horizontal <a href="/facts/Row_(database)/PIpv7c9e">rows</a>, the <a href="/facts/Cell_(database)/5INvK1Vd">cell</a> being the unit where a row and column intersect. A table has a specified number of columns, but can have any number of rows. Each row is identified by one or more values appearing in a particular column subset. A specific choice of columns which uniquely identify rows is called the <a href="/facts/Primary_key/veT9mAbo">primary key</a>.
"Table" is another term for <a href="/facts/Relation_(database)/Sj67AUyD">"relation"</a>; although there is the difference in that a table is usually a <a href="/facts/Multiset/bPFJGMDo">multiset</a> (bag) of rows where a relation is a <a href="/facts/Set_(computer_science)/ovoXUmF9">set</a> and does not allow duplicates. Besides the actual data rows, tables generally have associated with them some <a href="/facts/Metadata/qt35z79C">metadata</a>, such as <a href="/facts/Check_constraint/4oMErcot">constraints</a> on the table or on the values within particular columns.[dubious – discuss]
The data in a table does not have to be physically stored in the database. <a href="/facts/View_(database)/6B00yj6A">Views</a> also function as relational tables, but their data are calculated at query time. External tables (in <a href="/facts/IBM_Informix/jDdeW93c">Informix</a>
or <a href="/facts/Oracle_Database/FHv5g732">Oracle</a>,
for example) can also be thought of as views.

In many systems for computational statistics, such as <a href="/facts/R_(programming_language)/LSrkr8K8">R</a> and <a href="/facts/Python_(programming_language)/YbuGqofa">Python</a>'s <a href="/facts/Pandas_(software)/VKkTK8RL">pandas</a>, a data frame or data table is a <a href="/facts/Data_type/fcx5hgVL">data type</a> supporting the table abstraction. Conceptually, it is a list of records or <a href="/facts/Observation_(statistics)/IFEDysRP">observations</a> all containing the same fields or columns. The implementation consists of a list of <a href="/facts/Array_data_structure/BKGvF8AM">arrays or vectors</a>, each with a name.

Table (database) open-in-new

Table (database)