Oracle Introduction

Oracle Introduction

1.What is Oracle table?
    
A table is the basic unit of data storage in an Oracle database. The tables of a database hold all of the user accessible data. Table data is stored in rows and columns.

2.What is Oracle?
    
Oracle is relational database management system, which organizes data in the form of tables. Oracle makes efficient use of all system resources, on all hardware architecture, to deliver unmatched performance, price performance and scalability.

3. What is an Oracle view?
    
A view is a virtual table. Every view has a query attached to it. (The query is a SELECT statement that identifies the columns and rows of the table(s) the view uses.)
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4.What are the collection types in oracle?
    
Collection types are objects that contain multiple sets of values. There are two kinds of collection types:
varrays
object-type tables

5.What is a table space?
    
A database is divided into Logical Storage Unit called tablespaces.
A tablespace is a logical grouping of related data.
In Oracle, user data is logically stored in tablespaces which is physically stored in data files.

7.What is the difference between a relation and a relationship?

The difference between a relation and a relationship is that a relation is another name for a table, whereas a relationship is a way to correlate, or join, two or more tables.

8.Name two new features of Oracle8?
    
New features of Oracle8 include partitioned tables, index-only tables, and improved parallelism.

9.What are the three types of DML (Data Manipulation Language) statements?
    
There are three types of DML statements are :
INSERT
UPDATE
DELETE
MERGE .

10.What is a log group?
    
A log file group is a set of identical redo log files. This provides redundancy to protect against media failure.

11.What are Clusters?
    
Clusters are groups of one or more tables physically stores together to share common columns and are often used together.

12.What are the advantages of views?
    
Provide an additional level of table security, by restricting access to a predetermined set of rows and columns of a table.
Hide data complexity.
Simplify commands for the user.
Present the data in a different perspective from that of the base table
Store complex queries.

13.What are the various types of queries?
    
The types of queries are :
Normal Queries
Sub Queries
Co-related queries
Nested queries
Compound queries

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