Relational Database Structure and Terminology Conclusion
This module introduced you to the structure of a relational database and some of the terminology used to describe it.
You learned that the structure of a relational database is based on the relational model.
You also learned that the largest structure in a relational database is a table, which contains fields, records, and a primary key.
You discovered that using the primary-key field to link tables allows data to be accessed in a relational database.
Finally, you learned that Structured Query Language (SQL) is the programming language used to create relational databases, and that a relational database management system (RDBMS) is a software package used to manage relational databases.
Now that you have completed the lessons in this module, you should be able to:
- Describe the relational database model
- Describe the structure of a relational database
- Explain how relational database tables are linked to access data
- Explain why SQL is the lingua franca of relational databases
- Describe the functions of a relational database management system
Each database model provides a unique formal structure for its database type. As you might expect, there are advantages and disadvantages to each formal structure.
The structure of a relational database was briefly discussed in this module.
It is beyond our scope to compare and contrast the relational model with the other three.
Both the hierarchical and network models are used in many legacy database systems.
However, you will rarely find new databases created from these two older models. The object-oriented model, on the other hand, is relatively new. It caught on in the mid-90s and continues to gain in popularity. In fact, some relational databases such as Oracle incorporate elements from the object-oriented model. Suffice to say that the advantages of the relational model outweigh its disadvantages; of the four 1)relational, 2)Object-oriented, 3)hierarchical, 4)network, it is the model of choice for most businesses.
Use cases for implementing Object-Oriented Database Models
Object-oriented database models (OODBMs) are an alternative to the traditional relational database models. They provide a more natural way of modeling real-world entities by combining the principles of object-oriented programming (OOP) with database management. OODBMs can be particularly useful in specific use cases, such as:
- Complex data structures: OODBMs are well-suited for handling complex data structures, such as nested objects, hierarchies, or graphs. They can store objects and their relationships directly, making it easier to represent and manage complex data models.
- Multimedia and large objects: OODBMs are adept at handling multimedia data, such as images, audio, and video files, as well as large and complex objects like geographical data or scientific data. They can store and manage these types of data more efficiently than relational databases, which often struggle with large binary data.
- Object-oriented applications: OODBMs are a natural fit for object-oriented applications, as they allow for seamless integration between the database and the application's object model. This reduces the need for complex data mapping and conversion between the application and the database, simplifying development and maintenance.
- CAD/CAM and engineering applications: Object-oriented databases are well-suited for Computer-Aided Design (CAD), Computer-Aided Manufacturing (CAM), and other engineering applications that require complex data modeling and manipulation, such as representing 3D models, assemblies, or design hierarchies.
- Real-time systems: OODBMs can provide faster response times and better performance for real-time systems, where data must be accessed and manipulated quickly and efficiently. The direct storage of objects and their relationships can lead to faster retrieval and updates than relational databases.
- Simulation and modeling: Object-oriented databases are suitable for simulation and modeling applications, where complex data structures and relationships need to be represented and manipulated. Examples include traffic simulations, weather modeling, or financial simulations.
- Artificial intelligence and expert systems: OODBMs can be useful in artificial intelligence (AI) and expert systems, where knowledge representation, reasoning, and complex relationships play a significant role. They can store and manage complex data structures and relationships more efficiently than relational databases.
- Version control and history tracking: Object-oriented databases can easily handle version control and history tracking, as they can store different versions of objects and their relationships. This feature is useful in applications where tracking changes over time is essential, such as version control systems, document management systems, or configuration management systems.
In summary, object-oriented database models are well-suited for use cases involving complex data structures, multimedia data, object-oriented applications, CAD/CAM, real-time systems, simulation and modeling, artificial intelligence, and version control. They provide a more natural and efficient way of modeling and managing complex data and relationships compared to traditional relational databases.
This module introduced you to the following terms:
- data: The "raw facts" stored in a database.
- data definition language (DDL): A collection of programming statements that describe and define data and data relationships in a database.
- data integrity: A term used to describe the quality (in terms of accuracy, consistency, and validity) of data in a database,
in the sense that values required to enforce data relationships actually exist. Problems with data integrity occur when a value in one table that’s supposed to relate to a value in another can’t, because the second value either has been deleted or was never entered.
- data manipulation language (DML): A collection of programming statements used to manipulate a database.
- database model: A formal structure for organizing and linking data in a database.
- field: The smallest structure in a table; contains data describing the subject of a table.
- foreign key: A field (or combination of fields) used to link tables; a corresponding primary key field occurs in the same database.
- hierarchical model: A database model that organizes data in a top-down (inverted tree) structure.
- information: A collection of "raw facts" (data) organized in such a way that they have value
beyond the value of the facts themselves.
- network model: An extension of the hierarchical model. (See hierarchical model.)
- oject-oriented model: When database capabilities are combined with object programming language capabilities, the result is an object database management system (ODBMS).
- primary key: A field (or combination of fields) that uniquely identifies a record in a table.
- query: (v) To extract data from a database; (n.) a set of SQL statements for extracting particular data from a database.
- record: A particular instance of the subject of a table.
- relational database: A relational database is a database that conforms to the relational model, and refers to the data and schema of the database.
- Relational Database Management System (RDBMS): A software package that manages and provides access to a database.
These packages follow Codd’s 12 rules of relational databases and normally use SQL to access data.
- relational model: A formal structure that organizes data into relations (i.e., tables).
- table: A collection of data arranged in rows and columns. A table is the largest structure in a relational database.
- user views: Saved queries created with SQL. User views specify which users are permitted access to what data in a database.
In the next module, database design strategy and design tools will be discussed.
Relational Database Quiz
Before moving on to the next module, click the Quiz link below to check your knowledge of relational database structure and terminology.
Relational Database - Quiz
Ad Relational Database Design