What is a data domain?
"data domain" is a term used in database fields and data management. It refers to the range of acceptable values that may contain a specific line or field. The enforcement of data domains maintains information in the database consistent and in acceptable parameters and avoids situations in which the databases either create nonsensical results or are unable to answer specific questions for lack of sufficient information. Defining a data domain is performed by a database programmer, which often sets a list of correct values for the input field in the program.
The simplest way to understand the concept of data domain is to explore an example. Consider the field in the employee database in which the end user should record the employment status of individual employees. Each employee in the organization will be either a current or past employee; Therefore, these are the only acceptable items in the data domain for this field. When creating a database, a programmer of typically suggests that this isThe only acceptable response for someone who enters data in the "state of employees".
Another, more complicated example of a data domain would be an employee's telephone number. In the US, the data domain in this area would only have to be limited to numbers, along with a maximum length of 10 characters; In other words, the area of the area plus a seven -digit phone number. The programmer who wanted to force an even stricter level of control over the data domain could program it so that only real codes and prefixes of the area can be used, preventing individuals from attempting to claim (999) 999-9999 as their phone number. In both examples, the limits headed to efficient data domains are performed using a tool known as a reference table.
Acceptable data values are usually stored in the so -called reference table. The reference table is the Linked table to the database that contains acceptable valuesor ranges of values for data for specific tables in the database. The information entered in the database is compared to the reference table to determine whether the user accidentally entered the invalid record. Invalid items are usually marked with an error message and call on the second opportunity to enter the correct value into the database.