AYB221 Lecture Notes - Database, Unique Key, Data Integration
Accounting Systems and Technologies Week 2
DATA BASE CONCEPTS, DESIGN AND MANAGEMENT
The Old Approach – Manual Data Management
- Key Coers Related to Today’s Busiess Eviroet
o Access to information is slow
o Data needs to be kept in some order
o It is expensive
o Concurrent access is difficult
o There is normally only one copy
o Remote access is difficult
o Integrity of data
What is a Database?
- A database is a shared computerized structure that captures, stores and relates data
- A Database system is a system of hardware, software, people, procedures and data that
allow the capture, storage, management and use of data within a database environment
- Examples of Databases
- Aoutig Systes, Mediak, Motor Vehile Registratio, Busiess Custoers…
Relational Database
- A database that stores data in a number of tables
o Table: a collection of columns (attributes) and rows (objects) that describe an entity
o Record: a connected set of fields that describe a person, place or thing
o File: a file is a collection of records that are related
o Primary key: an attribute (or column) that uniquely identifies an object (or row)
o Composite key: a combination of more than one primary key.
Advantages of Database Systems
- Eliminates data repetition
- Eliminates inconsistent data
- Allows for organizational wide data sharing
- Reduced program maintenance
- Increased flexibility and speed
Why a Database Approach?
- Views data as an organisational resource that should be used by, and managed for, the
entire organisation, not just the originating department or function.
- The focus is on data integration and data sharing.
- Integration is achieved by combining individual application databases into larger pools of
data that can be accessed by many application programs.
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Document Summary
Key co(cid:374)(cid:272)er(cid:374)s related to today"s busi(cid:374)ess e(cid:374)viro(cid:374)(cid:373)e(cid:374)t: access to information is slow, data needs to be kept in some order. It is expensive: concurrent access is difficult, there is normally only one copy, remote access is difficult. A database is a shared computerized structure that captures, stores and relates data. A database system is a system of hardware, software, people, procedures and data that allow the capture, storage, management and use of data within a database environment. A(cid:272)(cid:272)ou(cid:374)ti(cid:374)g syste(cid:373)s, medi(cid:271)a(cid:374)k, motor vehi(cid:272)le registratio(cid:374), busi(cid:374)ess custo(cid:373)ers . Views data as an organisational resource that should be used by, and managed for, the entire organisation, not just the originating department or function. The focus is on data integration and data sharing.
