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COMPUTER SOFTWARE APPLICATION - CITS

Data Models, Concept of DBA, Database Users

Data Types
Data types define the kind of data that can be stored in a column of a database table. Different database
management systems (DBMS) might support slightly different sets of data types, but here are some common
categories:
1 Numeric Types
- Integer: Whole numbers (e.g., 1, -5, 100).
- Float/Double: Approximate decimal numbers with a specified precision (e.g., 3.14, -0.001).

2 Character Strings
- Char: Fixed-length character string (e.g., ‘Hello’).
- Varchar: Variable-length character string (e.g., ‘StudentName’).
3 Date and Time Types

- Date: Represents a date (e.g., ‘2023-08-31’).
- Time: Represents a time (e.g., ‘15:30:00’).
- Timestamp: Represents a date and time (e.g., ‘2023-08-31 15:30:00’).
4 Boolean Type
- Boolean: Represents true or false values.
5 Binary Types

- Blob (Binary Large Object): Stores binary data, such as images or files.
6 Enumeration Types:
- Enum: Represents a predefined set of values (e.g., ‘red’, ‘green’, ‘blue’).
7 Composite Types

- JSON or XML: Stores structured data in JSON or XML format.
Data Models
In the realm of Database Management Systems (DBMS), a data model refers to a set of tools designed to
condense the database’s description. Data models offer a clear representation of data, aiding in the creation of
an effective database. They guide us from conceptualizing data design to its accurate implementation.
Types of Relational Models
1 Conceptual Data Model

2 Representational Data Model
3 Physical Data Model
1 Conceptual Data Model
The conceptual data model presents a broad overview of the database, focusing on high-level aspects. It
serves to comprehend the database’s necessities and demands. This model is pivotal during requirement
gathering, preceding the actual database design by Database Designers. A prominent example of this
approach is the entity/relationship (ER) model. The ER model delves into entities, relationships, and attributes,
providing a foundation for database designers. Moreover, this concept facilitates discussions with non-technical
stakeholders, aiding in understanding and addressing their requirements.
1 Entity-Relationship Model (ER Model): The ER Model stands as a top-tier data model employed to outline
data and their interconnections. Essentially, it serves as a conceptual blueprint for databases, enabling an
uncomplicated depiction of data perspectives.
Components of ER Model
1 Entity: An entity represents a real-world object, whether it’s a person, place, concept, or item. In an ER
Diagram, entities are depicted using rectangles.

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CITS : IT&ITES - Computer software application - Lesson 18 - 36