Fundamentals of Databases

• What is a database?

  A persistent organized store of related data
• Why is a database structured?

  To facilitate efficient management and processing
• What is a table in a database?

  A collection of data relating to an entity
• What is a record in a database?

  A collection of data about a single entity
• What is a field in a database?

  A unique piece of data about an entity
• What is a field name?

  An identifier for a single piece of data
• What is an entity in a database?

  Something in the real world we store data about
• What is a record in the context of a database?

  One instance of an entity in a database
• What is an attribute in a database?

  A characteristic of an entity
• What is a database management system (DBMS)?

  Applications that access databases using an intermediate program
• Why use a database management system?

  It separates storage from applications for abstraction
• How does a DBMS enhance security?

  It acts as a guardian of the data
• What does CRUD stand for in database management?

  Create, Read, Update, Delete
• What is a relational database?

  A database with separate tables for each entity
• What is a flat-file database?

  Stores all data in a single table
• What is a primary key?

  A field that uniquely identifies each record
• What is a foreign key?

  Attributes that link to another entity
• What does referential integrity ensure?

  All primary key values match foreign keys
• What are the advantages of using a DBMS?

  • No data redundancy
  • Manages structure changes without affecting programs
  • Specialized for fast CRUD access
  • May provide security levels
• What is normalization in databases?

  • Process of reorganizing data
  • Eliminates data redundancy
  • Groups related data logically
• What is 1st Normal Form (1NF)?

  No repeating or grouped attributes
• What is 2nd Normal Form (2NF)?

  In 1NF with all non-key attributes dependent on primary key
• What is 3rd Normal Form (3NF)?

  • In 2NF
  • with no attributes depending on another attribute
• What does it mean for attributes to be non-transiently dependent on the primary key?

  All attributes depend solely on the primary key
• What are the ACID principles?

  • Atomicity
  • Consistency
  • Isolation
  • Durability
• State the purpose of the first principle of ACID

  • Atomicity is the requirement that a transaction must be fully processed or not processed at all, removing the possibility of a partially completed transaction. 
• State the purpose of the second principle of ACID

  Consistency is the requirement that a transaction cannot compromise referential integrity.
• State the purpose of the third principle of ACID


  Isolation is the requirement that when a record is being retrieved and a user edits or updates it, it is locked from other users. Once the transaction is complete, others can then access the record
• State the purpose of the fourth principle of ACID


  Durability is the requirement that once a transaction has been performed, the database change needs to be written immediately to secondary storage so that it will not be lost during power failures.
• What is commitment ordering?

  • is a concurrent control technique that ensures transactions are executed in order based on their dependencies
• WHat is serialisation?

  • makes sure transactions do not overlap in time