Technical Interview Questions and Answers :: Virtusa
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A binder allows a two-argument function object to be used as a single-argument function by binding one argument is a value.
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View created with base table, force view created without base table..
A View is a database object that is a logical representation of a table. It is derived from a table but has no storage space of its own and often may be used in the same manner as a table.
The are three levels of abstraction:
* Physical level: The lowest level of abstraction describes how data are stored.
* Logical level: The next higher level of abstraction, describes what data are stored in database and what relationship among those data.
* View level: The highest level of abstraction describes only part of entire database
A data base schema which is specified by a set of definitions expressed by a special language is called DDL. Data Definition Language (DDL) is used to define and manage all the objects in an SQL database.
It is a special language used to manipulate the Data. Data Manipulation Language (DML), which is used to select, insert, update, and delete data in the objects defined using DDL.
The PRIMARY KEY is the column(s) used to uniquely identify each row of a table.
A FOREIGN KEY is one or more columns whose values are based on the PRIMARY or CANDITATE KEY values from the database.
A UNIQUE KEY is one or more columns that must be unique for each row of the table.