Flat File

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What Does Flat File Mean?

A flat file database is a collection of records in which the data follows a uniform format and follows rules on value types where applicable. The database is flat because every line only holds one data input, depending on the categorization of the columns.


Flat file databases store plain text records and binary files that are needed for a specific purpose in a single directory for easy access and transfer. Mainstream operating systems (OSes) like Windows, Linux, and macOS all use a series of flat files to launch and run the OS, all while conserving storage space and ensuring none of the files essential to running the OS are damaged or altered.

One of the most common flat file examples is a comma-separated values (CSV) file. In a CSV file, table data is represented by lines of ASCII text. The value of each table cell in the example below is separated by a comma and each row is represented by a new line in Notepad.

Flat File Database Keeping data in flat files provides a reliable and trustworthy method for transferring data remotely, while ensuring data retains its original state and authenticity. Since flat files do not require extensive storage space, they are often used in data warehouse and data lake projects to store large volumes of unstructured and semi-structured data.

Techopedia Explains Flat File

Because of the flat structure, data in a flat file cannot be manipulated or analyzed easily without being imported into another application. The ease of importing a flat file database depends primarily on its structure. Inappropriately importing a flat file into a database management application may leave additional characters, spaces, and misplaced data points that could affect the credibility and integrity of any data analysis and manipulation.

Structure of Flat File Databases

In a flat file database, the first row in the database contains the keys and fields to identify and categorize data points. The following rows all represent data points where each row—or in some cases, a collection of cells—represents a single record.

There are two structures flat file setups can use depending on how the data was gathered and what specifications were selected when converting the data from a manageable file to a flat file.

  • Fixed width – Flat files with a fixed width have each data entry isolated to a single column with a fixed width. The column could either hide part of the data if it required space longer than its width or provide sufficient space with white space.
  • Delimited – Delimited flat files, also known as CVS files (Comma-Separates Values files), do not rely on pre-programmed cells and columns to divide data entries. Instead,they use digital dividers to separate fields from one another. The dividers range from commas and pipes to semicolons and a tab character with a set number of spaces.

Flat Files and Data Lakes

The variety of structures and storage formats are what’s allowing flat file databases to make a comeback into modern data sciences and analysis in the form of data lakes.

The efficiency of flat file databases allows them to be used in storing and then managing big data, which can be used to train Artificial Intelligence (AI) and machine learning (ML) applications.


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Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.