Conceptual Database Design: Structure & Advantages
Conceptual Design of Databases
Software
It is the database management system, in charge of managing the databases.
Data
It includes the need to store data and metadata, which describe what is stored in the database.
Users
People who manipulate system data. There are three categories:
- End Users: Those who use data from the database for daily work that need not have to do with computers. Normally, they do not use the database directly, but use applications built for them to facilitate handling of the data. These users access only certain data.
- Developers: Analysts and programmers responsible for generating end-user applications.
- Administrators: Also called DBA (Data Base Administrator) is responsible for administering databases.
Keep in mind that user needs are very different depending on the type of user. End users are concerned with ease of use; developers, with the power and flexibility of languages built into the database system; and managers, with advanced management tools for the database.
Structure of a Database
Databases are made of (as previously discussed) data and metadata. Metadata is data (forgive the redundancy) that serves to specify the structure of the database, for example, what type of data is stored (if text, numbers, or dates), what name is given to each data (name), how they are grouped, how they relate, etc.
Thus, there are two visions of the database:
- Logical Structure: Indicates the theoretical composition and distribution of the database. The logical structure is used to enable applications to use elements of the database without really knowing how they are stored. It is a structure that allows idealizing the database. Its elements are objects, entities, nodes, relations, links, etc. They do not really have an actual physical presence in the system. Therefore, access to data has to be a possibility of translating the logical structure into the physical structure.
- Physical Structure: It is the structure of data that is stored as files on the disk. The correspondence between the logic and physical structure is stored in the database (metadata).
Benefits of Databases
- Independence of data, programs, and processes. This allows changes without modifying the application code.
- Reduced redundancy: There is less need for repetition of data. However, only good designs have little data redundancy.
- Data Integrity: Fewer problems of losing data or inconsistencies.
- Increased data security: By limiting access to certain users.
- More documented data: Thanks to the metadata that can describe the information from the database.
- More efficient data access: The organization of the data results in more optimal performance.
- Less storage space: Due to better structuring of data.
Disadvantages of Databases
- Expensive installation: Control and database management requires powerful software and hardware.
- Requires skilled personnel: Due to the difficulty of handling this type of system.
- Implementation is long and difficult: Because of the above, the adaptation of staff is far more complicated and takes time.
- No real standards: This means excessive dependence on market trading systems, although a good portion of this technology is accepted as a de facto standard.