ISYS104 Lecture Notes - Lecture 5: Database Application, Data Type, Dbase
31 May 2018
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Chapter 5- Database Processing
Q1: What is the purpose of data base?
- To organise and keep track of things
- Spreadsheets do that too
- Keep lists of single concept, e.g. student test scores in a single subject
- Databases
- Keep lists that involve multiple themes/concepts, e.g. student grades, emails from
students, office visits etc.
- The purpose of a database is to keep track of things that involve more than one theme
Q2: What is Database?
- A database is a self-describing collection of integrated records
- Hierarchy of data elements
- Bytes/data are grouped into columns/fields
- Columns are grouped into rows/records
- Rows are grouped into tables/files
- Collection of tables plus relationships among rows
- Also iludes etadata
- Describes the structure of the database
Relationships among rows
- Values in one table may relate to rows/records in other tables
o Key
- A column or group of columns that identifies a unique row in a table
- Each table has a key
- Often called the primary key
o Foreign keys
- Fields, other than the primary key, that are used to connect to a table where the
field is the primary key
o Relational databases
- Databases using tables, keys and foreign keys
Metadata
- Database is self-describing
- Contains descriptions of its data, e.g. Field properties in Access
- Metadata
- Data that describe data
- Make databases more useful
- Make databases easier to use
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- Examples of metadata
- Field name
- Data type
- Field properties
- Description
Q3: What are the Components of a Database Application System?
- A database by itself is not very useful to business professionals
- A database application system makes the data from a database more accessible and
useful
- A database application system comprises:
- A user who uses the database application
- A database application that consists of forms, reports, queries and other application
programs
- A database management system to process the database
- A database containing tables, relationships and metadata
Components of a Database Application System
User → Data base applications → DBMS → Database
- Forms - Database - Tables
- Reports management - Relationships
- Queries systems - Metadata
- Apps
- Programs
Database Management Systems (DBMS)
- A DBMS is a program used to create, process and administer a database
- Usually licensed from vendors
- DBMS products include Microsoft Access, Oracle, MySQL, DB2
- A DBMS and a database are different
- A DBMS is a software program
- A database is a collection of tables, relationships and metadata
Processing the Database
- A major function of a DBMS is to process the data in a database
- Four processing operations of a DBMS are Read, Insert, Modify, Delete
- Structured Query Language (SQL)
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Document Summary
To organise and keep track of things. Keep lists of single concept, e. g. student test scores in a single subject. Keep lists that involve multiple themes/concepts, e. g. student grades, emails from students, office visits etc. The purpose of a database is to keep track of things that involve more than one theme. A database is a self-describing collection of integrated records. Collection of tables plus relationships among rows. Values in one table may relate to rows/records in other tables: key. A column or group of columns that identifies a unique row in a table. Often called the primary key: foreign keys. Fields, other than the primary key, that are used to connect to a table where the field is the primary key: relational databases. Databases using tables, keys and foreign keys. Contains descriptions of its data, e. g. field properties in access. A database by itself is not very useful to business professionals.
