Editing Data model (section)

=== Database model ===
{{Main|Database model}}

A database model is a specification describing how a database is structured and used.

Several such models have been suggested. Common models include:
; [[Flat-file database|Flat model]]
: This may not strictly qualify as a data model.  The flat (or table) model consists of a single, two-dimensional array of data elements, where all members of a given column are assumed to be similar values, and all members of a row are assumed to be related to one another.
; [[Hierarchical model]]
: The hierarchical model is similar to the network model except that links in the hierarchical model form a tree structure, while the network model allows arbitrary graph.
; [[Network model]]
: This model organizes data using two fundamental constructs, called records and sets. Records contain fields, and sets define one-to-many relationships between records: one owner, many members. The network data model is an abstraction of the design concept used in the implementation of databases.
; [[Relational model]]
: is a database model based on first-order predicate logic. Its core idea is to describe a database as a collection of predicates over a finite set of predicate variables, describing constraints on the possible values and combinations of values. The power of the relational data model lies in its mathematical foundations and a simple user-level paradigm.
; [[Object–relational model]]
: Similar to a relational database model, but objects, classes, and inheritance are directly supported in [[database schema]]s and in the query language.
; [[Object–role modeling]]
: A method of data modeling that has been defined as "attribute free", and "fact-based". The result is a verifiably correct system, from which other common artifacts, such as ERD, UML, and semantic models may be derived. Associations between data objects are described during the database design procedure, such that normalization is an inevitable result of the process.
; [[Star schema]]
: The simplest style of data warehouse schema. The star schema consists of a few "fact tables" (possibly only one, justifying the name) referencing any number of "dimension tables". The star schema is considered an important special case of the [[snowflake schema]].

<gallery class="center">
Image:FigFileConvert000a.svg|[[Flat file database|Flat model]]
Image:Hierarchisches Datenbankmodell.svg|[[Hierarchical model]]
Image:Network DB model.svg|[[Network model]]
Image:Relational model concepts.png|[[Relational model]] 
Image:Company_codm.png|Concept-oriented model 
Image:Star-schema.png|[[Star schema]]
</gallery>