Data Topics

This video shows a flat file database and examines database terminology related to it.

• Data duplication: data repeated in a table
• Data redundancy: the unnecessary duplication of data
• Data integrity: the accuracy or correctness of data
• Table/ Entity / Relation: a cluster of data representing one thing stored in rows and columns
• Row/Record/Tuple: collection data stored about one item in the table/ entity/ relation
• Column/Field/ Attribute: the facts stored in each record
• Primary Key: unique identifier for each record
• Foreign Key: field in a table that matches a primary key in another table allowing the tables to be joined
• Insertion Anomalies: The inability to add information to a database because extra data is required to add it to the database (in our example - we couldn't add supplier details before receiving a movie)
• Update Anomalies: changes must be made in multiple locations (in our example: if a supplier moved the address would need to be changed in many records)
• Deletion Anomalies: deleting a row causes other data to be deleted (in our example: removing a movie causes supplier details to be deleted)