What is a database teach ICT?
What is a database teach ICT?
DEFINITION: A database is a collection of data or information which is held together in an organised or logical way. Or, they might give you a scenario such as an estate agents, a cinema or a GP surgery and then ask you to give an example of a database that might be used in that organisation.
What are the types of database in Ict?
Types of Databases. There are several common types of databases; each type of database has its own data model (how the data is structured). They include; Flat Model, Hierarchical Model, Relational Model and Network Model.
What is a record teach ICT?
A record is all of the data about one person or one thing. A record is made up of one or more ‘fields’. For example a name and address database could have one record such as this: “Joe Blogs”, “34 Wyvern Road” , “Manchester”, “UK”, “MN253PE” This is a complete record, with each field separated by a comma.
What is relational database igcse?
Relational Databases. A ‘relational’ database is one that contains two or more tables of data, connected by links called relationships.
What are the disadvantages of relational database?
Disadvantages of Relational Database
- Cost. The underlaying cost involved in a relational database is quite expensive.
- Performance. Always the performance of the relational database depends on the number of tables.
- Physical Storage.
- Complexity.
- Information Loss.
- Structure Limitations.
What are the different types of relationship in a database?
Many-to-Many. In a many-to-many relationship, a row in table A can have many matching rows in table B, and vice versa. A many-to-many relationship could be thought of as two one-to-many relationships, linked by an intermediary table. The intermediary table is typically referred to as a “junction table” (also as a “cross-reference table”).
How are the tables in a relational database linked?
The tables in a relational database are linked by the key field in one table being added as a foreign key in another table to form a relationship between the entities. Consider a library database.
How does a doctor use a relational database?
A doctor wishes to use a database to keep track of his patients’ test results. It needs to record: test results. A flat-file database table set up to store the data might look like the one below (the key field has been ignored). The problems that can then occur:
How is data stored in a relational database?
The key difference between a relational database and a flat-file database is that in a relational database the data is grouped into entities and stored in multiple linked tables. What is an entity and how are they related to database tables? An entity is a “real world thing” about which data can is held in a database. Examples of entities include: