Data is a raw and unorganized fact that is required to be processed to make it meaningful. Data management is the process of absorbing, storing, organizing and maintaining data.
Uses cards and papers. For each object that is required there needs to be a file and these files are stored in cabinet. For searching we find the right cabinet then the right file then the right information.
| Limitations |
|---|
| Prone to error |
| Difficult to retrieve or update |
| Difficult to cross reference |
| Limited to small size |
Uses permanent files to store data. Different application programs define manage and maintain their own data
Sales application program is used to manipulate the sales files and the contracts application program is used to manipulate the contracts file. The attributes Client and PropertyForRent are common to both application programs which causes the same information to be duplicated.
| Limitations |
|---|
| Data redundancy which is the same information duplicated several times |
| Data Inconsistency which is where various copies of the same data are conflicting |
| Higher storage and access cost due to data redundancy |
| Data isolation which is where changes made by one application program are not visible in other application programs |
| Data dependency which is where the data and the application program are related so any change needed in the data structure would also have to change the application program |
| Difficulty in accessing data useful data maybe held by other application programs |
The reason we have all these problems in the file-based approach is that the data is embedded with the application program rather than being two separate entities.
A database is a repository that is designed to support efficient data storage, retrieval and maintenance. A Database Management System(DBMS) is a software that enables users to define, create, maintain, and control a database. Using a database separates the logical view which is how the end user sees the data and the physical view which is how the data is actually stored on a storage media. Using a Database application program we can interact with a database by using SQL statements.