Database definitions Flashcards
What does a record look like in a database table?
It is a row of data./tuples.
What does a field look like in a database table?
It is a column of data./attributes.
What is a flat file database?
It contains only a single table, can be created very easily using either database or spreadsheet software.
Capturing data - Name all types of data collection methods.
1.Paper based forms
2.Optical character recognition
3.optical mark recognition
Capturing data - what are the 4 stages of handling data?
Capturing:- How do we get the data into the database in the first place?
Selecting:- How do we then query the data and retrieve it?
Managing:- How do we manage, manipulate, add, edit and delete the data?
Exchanging:- how do we exchange the data with other people/systems?
Selecting data - What are the methods or selecting and retrieving collected data?
- SQL (Structured Query Language)
- QBE (Query By Example)
Managing Data - What are methods of managing data?
SQL
Exchanging Data - What are methods of exchanging data?
- XML (Human readible)
- JSON (Human readible)
- CSV
- Electronic Data Interchange (EDI) automatic data transfer.
What rules are needed for a table/database to have to reach FIRST Normal form?
1.All field names must be unique.
2.Values in fields should be from the same domain.
3.Values in fields should be atomic.
4.No two records can be identical.
- Each table needs a primary key.
What rules are needed to make a database SECOND Normal Form?
- The data is already in 1NF
- Any partial dependecies have been removed.
Steps on how to deal with Many-to-many relationships?
- Creating a linking table.
- Assigning the primary keys from the two initial tables as the composite key for the new linking table.
- flipping the Many-to-Many crows-feet relationshio to become two seperate one-to-many relationships joined by the new table.
What are the rules for a table/database to reach THIRD normal form?
- The data is already in 2NF
- Any transitive dependencies have been removed.
