DCIT 55 - Reviewer for ER Model and Database Concepts

An attribute that uniquely identifies any given entity.

This command marks and saves the current point in the processing of a transaction.

It provides a detailed accounting of all tables found within the user/designer-created database.

<p>It enables programmers to view data logically rather than physically.</p> Signup and view all the answers

<p>It is an entity that can exist apart from one or more related entities.</p> Signup and view all the answers

<p>It terminates the current transaction and undoes any changes made during the transaction.</p> Signup and view all the answers

<p>A Multivalued Attribute is an attribute that can have many values. For example, in a student table, the 'hobbies' attribute can be multivalued, allowing a student to have multiple hobbies.</p> Signup and view all the answers

<p>A Secondary Key is a key used strictly for data retrieval purposes. In contrast, a Candidate Key is a super key without redundancies and can be used to uniquely identify a row in a table.</p> Signup and view all the answers

<p>A COMMIT statement is used to permanently save any transaction into the database. Once a transaction is committed, its changes become permanent and visible to other transactions.</p> Signup and view all the answers

<p>An ER diagram is a graphical representation of a conceptual database viewed by an end-user. It forms the basis of an ER model and is used to visually depict the entities, attributes, and relationships in a database.</p> Signup and view all the answers

<p>A Derived/Computed attribute is an attribute whose value may be calculated from other attributes. For example, in a sales database, the 'total_sales' attribute of a salesperson can be a derived attribute calculated by summing the 'sales_amount' of individual transactions.</p> Signup and view all the answers

<p>A single-user database supports only one user at a time and is typically a desktop database running on a personal computer. Its main limitation is the inability to handle concurrent access or support multiple users simultaneously.</p> Signup and view all the answers