Database Questions

A relational database is a digital database based on the relational model of data, a database structured to recognize relations between stored items of information. A software system used to maintain relational databases is a relational database management system.

Computer database in which all data is stored in Relations which (to the user) are tables with rows and columns. Each table is composed of records (called Tuples) and each record is identified by a field (attribute) containing a unique value. Every table shares at least one field with another table in 'one to one,' 'one to many,' or 'many to many' relationships. These relationships allow the database user to access the data in almost an unlimited number of ways, and to combine the tables as building blocks to create complex and very large databases.

High level data models provide the concepts that are close to the way many users perceive data

The description of a data base is called the database schema , which is specified during database design and is not expected to change frequently . A displayed schema is called schema diagram .We call each object in the schema as schema construct.

The time complexity of sequential search is O(n)

A view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored .

They describe the details of how data is stored in the computers

Database provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.

Can’t delete a row from primary table if there are related rows in secondary table.