A current database is a database that stores only currently-accurate data. A database is a collection of facts typically arranged in tables. The purpose of a database is to expedite data retrieval and analysis, making it a simple matter to access information by using the Structured Query Language (SQL) programming language. Current databases are one of the two primary types of databases; the other is known as a temporal database. A current database asserts, by its definition, that all information currently contained in the database is up-to-date at the specific instant of access.
To understand current databases, it is useful to think of them in comparison to temporal databases. In a temporal database, each piece of information contains either a timestamp, a time interval, or some other piece of reference data stating the period through which the data is valid. For example, an employee record in any database might include the employee's name along with their personal information such as date of birth, position, salary, and so forth. In a temporal database, all of that data would also include a date listing the time period for which the information is accurate. This might mean including the date of hiring or a period of time during which the employees contract is active.
While the temporal database provides an instant reference so users can understand whether data is currently applicable, in contrast, a current database does away with this concept. No timestamp or time-recording information is stored alongside the individual records. Individuals using the database must therefore infer the relevance of the record's information to the current time period, simply by the fact that it still remains in the system. Obsolete or irrelevant time-expired data is deleted from a current database. This purge of data that is no longer current is critical to the functioning of current databases.
The advantage of a current database is that it reduces excess overhead in the system. Without a timestamp clogging up storage space for each entry into the system, a current database is sleek and trim compared to most of its temporal counterparts. Most current databases are not used in isolation, though. Companies will often have a current database of employee records — along with financial information and so on — coupled with temporal databases for older records or archives of past data. In this way, they have their current files always on-hand in a speedy and sleek database, but can still venture into past records in their temporal databases as well.