There are many functions a database management system (DBMS) serves that are key components to the operation of database management. When deciding to implement a DBMS in your business, first you must decide what type of DBMS you want. Common types of DBMS are the relational, network, hierarchy and object oriented models. Each kind of database structure has its own pros and cons.
While each is unique in its own way, there are five standard functions of any kind of DBMS:
Ability to update and retrieve data
This is a fundamental component of a DBMS and essential to database management. Without the ability to view or manipulate data, there would be no point to using a database system. Updating data in a database includes adding new records, deleting existing records and changing information within a record. The user does not need to be aware of how DBMS structures this data, all the user needs to be aware of is the availability of updating and/or pulling up information, the DBMS handles the processes and the structure of the data storage.
Support concurrent updates
Concurrent updates occur when multiple users make updates to the database simultaneously. Supporting concurrent updates is also crucial to database management as this component ensures that updates are made correctly and the end result is accurate. Without DBMS intervention, important data could be lost and/or inaccurate data stored.
DBMS uses features to support concurrent updates such as batch processing, locking, two-phase locking, and time stamping to help make certain that updates are done accurately. Again, the user is not aware all this is happening as it is the database management system's responsibility to make sure all updates are stored properly.
Recovery of data
In the event a catastrophe occurs, DBMS must provide ways to recover a database so that data is not permanently lost. There are times computers may crash, a fire or other natural disaster may occur, or a user may enter incorrect information invalidating or making records inconsistent.
If the database is destroyed or damaged in any way, the DBMS must be able to recover the correct state of the database, and this process is called Recovery. The easiest way to do this is to make regular backups of information. This can be done at a set structured time so in the event a disaster occurs, the database can be restored to the state that it was last at prior to backup.
A disadvantage to this is any data or changes entered after the backup would be lost. A way to counteract this is to set the DBMS to provide a feature called Journaling. This involves keeping a log of all updates made to the database, it is maintained in a file separate from the database and can be obtained to re-update the database after it is recovered from the backup.
Security is the prevention of unauthorized users accessing the database. DBMS uses features such as encryption, authentication, authorization and views to provide security to the database. Encryption is when DBMS converts the data in a database to an indecipherable format. No unauthorized person trying to access this information will be able to read it. Authorized users will be able to see it in normal form.
Authentication is a technique in which the database administrator can identify the person accessing the database. Authorized users are given passwords and successful entry of a valid password will allow the user entry into the database, if a password is not successfully entered, the user will be denied access. Authorization is a set of rules that the database administrator (DBA) sets up to specify levels of usage that individuals or groups are allowed to have. Some users may only be allowed viewing options, while others may be allowed to both view/make changes.
In some circumstances, users may only be allowed to access certain pieces of the database, and be denied access to areas that does not relate to their specific needs. These are called permissions. In these cases, the DBA will assign workgroups, and these workgroups will be assigned levels of access. Views are when DBA allows certain users the ability to view the tables or fields that pertain to them, any other view does not exist for them in the database, DBMS does this behind the scenes and to the user it appears the information they see is the only existing data.
Data integrity is an important function in database management. This is a set of rules that DBMS provides to see data integrity is enforced, thus avoiding incorrect or inconsistent data. Types of integrity a DBMS provides are data type, legal values and format. Key integrity also falls into this function of DBMS. This enforces that the primary key of a record remains unique.
Without any of the above listed functions, a database would not be able to work effectively. Each of these functions plays an important role in database management.