Posted: October 6th 2012
Database is contains files, file contains records, record contains fields, field contains characters.
- Field is a logical grouping of characters into a word, a small group of words, or a complete number.
Attribute of field is:
- Field size -> size of computer displays.
- Field name -> unique name (field name can’t same).
- Data type -> Type of data. Data types among others text, numeric, autonumber, currency, date, memo, yes/no, hyperlink, object.
- File is a logical grouping of related records.
- Database is a logical grouping of related files.
- Record is a logical grouping of related fields
4 center in database:
- Member file
- Membership plans file
- Personal trainer file
- Training session file.
Examples of Data Management Terminology is:
- Entity (Person, place, thing, or event about which information is maintained)
- Attribute (Characteristic or quality describing a particular entity
- Primary Key (A field that uniquely identifies the record)
- Secondary Key (A field doesn’t identify the records uniquely)
- File processing system is computerized system that performs mathematical operations (manipulations) on input-data to transform it into the output (audio/video, graphic, numeric, or text) form desired by a system user.
- Database Approach is a single repository of data is maintained that is defined once and then accessed by many users.
Locating in database have 2 character, that is:
- Centralized Database
- Distributed Database
Table of difference between Centalized Database and Distributed Database
|1. Files are in one physical location
||1. Files are spread in many location
|2. Not require synchronization
||2. Need synchronization
|3. Delays (slow in access)
||3. Fast in access
|4. Data consistency is improved and security is easier
||4. Maintance of data is more complicated
A student has one schedule, a schedule belongs to one student.
A course has one professor, a professor has one or more courses.
A student has one or more courses. a course has one or more students.