Software that is used to manage data and information structured as fields, records and files. A database program is the heart of a business information system and provides file creation, data entry, update, query and reporting functions. The traditional term for database software is "database management system" (see DBMS
). For more about database structures, see DBMS
and database schema
User Interaction with a Database
Database programs let users create and edit single files interactively at the keyboard. However, as soon as they want data in one file to automatically update another, programming has to be done. That is where the faint of heart take their leave, and the techies take over. Following are the common interactive tasks.
Create a File (Table) and Set Index Order
Each field in a record is defined by name, type and length. In order to keep the file, also called a "table," in sequence, one or more fields are defined as key fields, upon which indexes are created and maintained. The index is updated whenever records are added or deleted or any data in a key field changes.
Create Data Entry Forms
Data entry is accomplished by designing a form to display each record. Data entry forms contain field validation, which determines what data can go in and what cannot.
In a single-user, one-file-at-a-time application, there is nothing to predefine here. Changing data is a matter of opening the file and selecting the EDIT mode. However, in a multiuser system, security must be administered and audit trails must be programmed.
Browse an entire file or select records. Selected records are usually created as a temporary file that can be sorted into a different sequence and, after viewing, can be deleted or saved for later use.
The ease with which a query can be composed determines how often users ask their own questions versus relying on IT staff. For example, retrieving data from two files, such as customers and orders, or vendors and purchases, requires knowledge of how to link the files for the query. Most database programs have a JOIN function, which creates a new file with data from two existing files. Once a query has been composed, it can be saved for use again.
Reports provide details and summaries in a more elaborate fashion than queries. Reports have page and column headers and can be sorted into order by multiple fields; for example, city within county within state. Once a report description has been composed, it can be saved for use again.
From time to time, it is necessary to add or delete fields, or change their lengths or possibly their names. This function is similar to creating the record structure in the first place, except that only modifications are made.