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Flat file

(also flat-file database)

Flat file definition

A flat file is a collection of alphanumeric data stored in a two-dimensional database (i.e., a database with rows and columns). A flat file is not connected to any other file, and the information generally has little or no additional formatting. A flat-file database is typically very simple, without any structures for indexing or identifying relationships between data records.

The term “flat file” can also refer to a Microsoft Word document saved in text-only format — or any other document with minimal or no formatting.

Examples of flat files

  • Comma-separated CSV file
  • Name-and-address lists
  • A sheet of paper with a name, address, and phone number

Flat-file database use cases

Flat files are commonly used in data warehouse and data lake environments.

Benefits of flat-file databases

  • Low overhead. The costs of creating and maintaining flat-file databases are relatively low.
  • Convenient. Flat-file databases are an easy and convenient way to store and manipulate large volumes of information.
  • Simple in design. Flat files are typically simpler to design and smaller than relational databases, making them great for basic uses.

Disadvantages of flat-file databases

  • Data redundancy. Flat files don’t make it easy to avoid data duplication because they only contain one relational table.
  • No database relationships. If you want to enforce database relationships or constraints, you’ll need a relational database management system.

See also: database concurrency