“Data domain” is a term used in fields of databases and data management. Refers to the range of acceptable values that a specific row or field can contain. The data domain application keeps the information in a database consistent and within acceptable parameters, avoiding situations in which the databases produce absurd results or cannot answer specific queries due to insufficient information. The definition of a data domain is done by a database programmer, who often stipulates a list of appropriate values for an input field in the program.
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Perhaps the easiest way to understand the concept of a data domain is to look at an example. Consider a field in an employee database where an end user must record the employment status of individual employees. Each employee of the organization will be a current or former employee; therefore, these are the only acceptable entries in the data domain for that field. When creating the database, the programmer usually indicates that these are the only acceptable responses for someone entering data in “Employee Status”.
Another more complex example of a data domain would be a field for an employee’s phone number. In the US, the data domain in this field would have to be limited to numbers only, along with a maximum length of 10 characters; in other words, an area code plus a seven-digit phone number. A programmer who wanted to impose an even tighter level of control over the data domain could program it so that only real area codes and prefixes could be used, preventing people from trying to claim (999) 999-9999 as their phone serial number. telephone. In any example, the limits imposed on the effective data domains are achieved using a tool known as a lookup table.
Acceptable data values are generally stored in what is known as a lookup table. A reference table is a table linked to a database that contains the acceptable values or ranges of values for data from specific tables in the database. Information entered into the database is compared to the reference table to determine if the user accidentally entered invalid input. Invalid entries are usually marked with an error message and prompt for a second chance to enter a correct value into the database.
