Set - 4

Question 1 :

Relational database management system

Answer :

A software system that manages data in a database and is based on the relational model. DBMSs have several components described in detail in Chapter 1.

Question 2 :


Answer :

A query language that interacts with a DBMS. SQL is a set of statements to manage databases, tables, and data.

Question 3 :


Answer :

Restrictions or limitations on tables and attributes. For example, a wine can be produced only by one winery, an order for wine can't exist if it isn't associated with a customer, having a name attribute could be mandatory for a customer.

Question 4 :

Primary key

Answer :

One or more attributes that contain values that uniquely identify each row. For example, a customer table might have the primary key of cust ID. The cust ID attribute is then assigned a unique value for each customer. A primary key is a constraint of most tables.

Question 5 :


Answer :

A data structure used for fast access to rows in a table. An index is usually built for the primary key of each table and can then be used to quickly find a particular row. Indexes are also defined and built for other attributes when those attributes are frequently used in queries.