All of the above are view levels of database.

In an indexed file, there is a list of keys of records number which are maintained in the master list . So, options 2 and 3 are correct.

Top to bottom approach is used in hierarchial schema because it basically is based on Parent and Child Relationship. The parent and child relationship type has basically 1 : N relationship.

There are few methods to get recovery of documents from deadlock. These are commit, rollback or abort.

A parser is an SQL or Oracle translator who verfies the syntax of the SQL and query.

It links two relations or transactions.

This is a correct query which shows only distinct data and no duplicate values.

Instance is a collection of the information stored in a database at a particular moment.

Updated.log is a table containing information about transaction.

Command processing is the part of concurency control and command line program to generate multiple no responses to SQL multi-process concurrency control of test.

Quel was the original query language for the Ingres dbms. It is now called SQL.

A Wait for graph is a directed graph used for deadlock detection in operating systems and relational database systems.

In binary search tree, it goes according to the root element. If item to be searched is less than root, then it seaches to the left of root otherwise to the right.

Hash value points to the element exactly using index.

Every software has a interface to interact with clients or user, similarly in between user and database, interface is provided in application.

Dulpicate data in database is called as data redundancy in database. In order to avoid redundancy we use the technique of normalization.

By locking the database it makes it unsharable and nobody can share it.

Triggers are SQL statements that are stored in the database catalog. Once triggers are activated by database events such as UPDATE, DELETE or INSERT, the triggers will execute either before or after the event that initiates them.

COUNT returns only the number of rows in which the expression is NOT NULL.

Select statement is used to fetch data from table and database or to process a data query.  

EER is an Enhanced Entity Relationship. EER model includes all the modelling constructs of the ER model. In ER model, all the types of superclass and sub class relationship are expressed but ISA (IS - A) relationship is denoted by triangle. EER model additional specialization and generalization relationship notations are for defining the superclass and subclass.

Query tree is an internal representation of SQL statements where the single parts that  are built stored separately.

Prof. Peter Chen is the founder and orginator of the ER model.

The * is used to specify all the columns from the table in an SQL statement.

 Syntax for creating a ROW LEVEL TRIGGERcode - CREATE OR REPLACE TRIGGER<trigger name><BETORE|AFTER><ACTION>ON <table name>FOR EACH ROW (THIS IS CORERCT CLAUSE USED IN)