Oracle Database Sql

Front 1

Check if a table exists in the current database schema...

Back 1

SELECT table_name

FROM user_tables

WHERE table_name = 'TABLE_NAME'

Hint 1

Select statement

Front 2

Check if a column exists in a table...

Back 2

SELECT column_name AS FOUND

FROM user_tab_cols

WHERE table_name = 'TABLE_NAME' AND column_name = 'COLUMN_NAME';

Hint 2

Select statement

Front 3

Change current schema...

Back 3

ALTER SESSION SET CURRENT_SCHEMA = new_schema;

Hint 3

Alter statement

Front 4

Statement to return Oracle database version

Back 4

SELECT * FROM v$version;

Hint 4

Select statement

Front 5

Evaluate the following query:

SELECT TRUNC(ROUND(156.00,-1),-1)

FROM DUAL;

Back 5

160

Front 6

The first DROP operation is performed on PRODUCTS table using the following command:

DROP TABLE products PURGE;

Then you performed the FLASHBACK operation by using the following command:

FLASHBACK TABLE products TO BEFORE DROP;

Describe the outcome of the FLASHBACK statement...

Back 6

It is not possible to recover the table structure, data, or the related indexes.

Front 7

True or False:

Group functions can be used on columns or expressions

Back 7

True

Front 8

True or False:

Group functions can be passed as an argument to another function.

Back 8

True

Front 9

True or False:

Group functions can be used only with a SQL statement that has a GROUP BY clause.

Back 9

False

Front 10

True or False:

Group functions can be used on only one column in the SELECT clause of a SQL statement.

Back 10

False

Front 11

True or False:

Group functions can be used along with the single-row function in the SELECT clause of a SQL statement.

Back 11

True

Front 12

True or False:

The data dictionary is created and maintained by the database administrator.

Back 12

False

Front 13

True or False:

The data dictionary views consist of joins of dictionary base tables and user-defined tables

Back 13

False

Front 14

True or False:

The usernames of all the users including the database administrators are stored in the data dictionary.

Back 14

True

Front 15

True or False:

The USER_CONS_COLUMNS view should be queried to find the names of the columns to which a constraint applies

Back 15

True

Front 16

True or False:

both USER_OBJECTS and CAT views provide the same information about all the objects that are owned by the user.

Back 16

False

Front 17

True or False:

Views with the same name but different prefixes, such as DBA, ALL, and USER, use the same base tables from the data dictionary.

Back 17

True.

Front 18

What are Group functions in Oracle?

Back 18

Group functions (a.k.a Aggregate functions) are built-in SQL functions that operate on groups of rows and return one value for the entire group. These functions include: COUNT, MAX, MIN, AVG, SUM, DISTINCT

Front 19

Describe "Database Schema"

Back 19

A database schema is a collection of metadata that describes the relationship between the data in the database. A schema can be simply described as the "layout" of a database or the blueprint that outlines how data is organized into tables.

Front 20

Describe "Schema Objects"

Back 20

Schema objects are database objects that contain data or that govern or perform operations on data. By definition, each schema object belongs to a specific schema. Common schema objects include: tables, indexes, and views.

Front 21

True or False:

Wildcard characters are only meaningful if the operator is LIKE or NOT LIKE

Back 21

True

Front 22

True or False:

Text cannot be combined with a column value using the concatenation operator unless single quotes surround the text.

Back 22

True