NetEase Most Frequently Asked Latest Oracle Interview Questions Answers
What is an ALERT?
An alert is a window which appears in the center of the screen overlaying a portion of the current display.
What is hash cluster?
Hash Cluster is a technique used to store the table for faster retrieval. Apply hash value on the table to retrieve the rows from the table.
What are the various constraints used in Oracle?
Following are constraints used:
NULL – It is to indicate that particular column can contain NULL values
NOT NULL – It is to indicate that particular column cannot contain NULL values
CHECK – Validate that values in the given column to meet the specific criteria
DEFAULT – It is to indicate the value is assigned to default value
What are cursor attributes?
Each cursor in Oracle has set of attributes which enables an application program to test the state of the cursor. The attributes can be used to check whether cursor is opened or closed, found or not found and also find row count.
What are SET operators?
SET operators are used with two or more queries and those operators are Union, Union All, Intersect and Minus.
How can we delete duplicate rows in a table?
Duplicate rows in the table can be deleted by using ROWID.
What are the attributes of Cursor?
Attributes of Cursor are
%FOUND
Returns NULL if cursor is open and fetch has not been executed
Returns TRUE if the fetch of cursor is executed successfully.
Returns False if no rows are returned.
%NOT FOUND
Returns NULL if cursor is open and fetch has not been executed
Returns False if fetch has been executed
Returns True if no row was returned
%ISOPEN
Returns true if the cursor is open
Returns false if the cursor is closed
%ROWCOUNT
Returns the number of rows fetched. It has to be iterated through entire cursor to give exact real count.
What is difference between SUBSTR and INSTR?
SUBSTR returns specific portion of a string and INSTR provides character position in which a pattern is found in a string.
SUBSTR returns string whereas INSTR returns numeric.
What is the parameter mode that can be passed to a procedure?
IN, OUT and INOUT are the modes of parameters that can be passed to a procedure.
What are the different Oracle Database objects?
There are different data objects in Oracle –
Tables – set of elements organized in vertical and horizontal
Views – Virtual table derived from one or more tables
Indexes – Performance tuning method for processing the records
Synonyms – Alias name for tables
Sequences – Multiple users generate unique numbers
Tablespaces – Logical storage unit in Oracle
What are the differences between LOV and List Item?
LOV is property whereas list items are considered as single item. List of items is set to be a collection of list of items. A list item can have only one column, LOV can have one or more columns.
What are privileges and Grants?
Privileges are the rights to execute SQL statements – means Right to connect and connect. Grants are given to the object so that objects can be accessed accordingly. Grants can be provided by the owner or creator of an object.
What is the difference between $ORACLE_BASE and $ORACLE_HOME?
Oracle base is the main or root directory of an oracle whereas ORACLE_HOME is located beneath base folder in which all oracle products reside.
What is the fastest query method to fetch data from the table?
Row can be fetched from table by using ROWID. Using ROW ID is the fastest query method to fetch data from the table.
What is the maximum number of triggers that can be applied to a single table?
12 is the maximum number of triggers that can be applied to a single table.
How to display employee records who gets more salary than the average salary in the department?
This can be done by this query –
Select * from employee where salary>(select avg(salary) from dept, employee where dept.deptno = employee.deptno;
1
Select * from employee where salary>(select avg(salary) from dept, employee where dept.deptno = employee.deptno;
What do you mean by GROUP BY Clause?
A GROUP BY clause can be used in select statement where it will collect data across multiple records and group the results by one or more columns.
What is an ALERT?
An alert is a window which appears in the center of the screen overlaying a portion of the current display.
What is hash cluster?
Hash Cluster is a technique used to store the table for faster retrieval. Apply hash value on the table to retrieve the rows from the table.
What are the various constraints used in Oracle?
Following are constraints used:
NULL – It is to indicate that particular column can contain NULL values
NOT NULL – It is to indicate that particular column cannot contain NULL values
CHECK – Validate that values in the given column to meet the specific criteria
DEFAULT – It is to indicate the value is assigned to default value
What are cursor attributes?
Each cursor in Oracle has set of attributes which enables an application program to test the state of the cursor. The attributes can be used to check whether cursor is opened or closed, found or not found and also find row count.
 |
| NetEase Most Frequently Asked Latest Oracle Interview Questions Answers |
What are SET operators?
SET operators are used with two or more queries and those operators are Union, Union All, Intersect and Minus.
How can we delete duplicate rows in a table?
Duplicate rows in the table can be deleted by using ROWID.
What are the attributes of Cursor?
Attributes of Cursor are
%FOUND
Returns NULL if cursor is open and fetch has not been executed
Returns TRUE if the fetch of cursor is executed successfully.
Returns False if no rows are returned.
%NOT FOUND
Returns NULL if cursor is open and fetch has not been executed
Returns False if fetch has been executed
Returns True if no row was returned
%ISOPEN
Returns true if the cursor is open
Returns false if the cursor is closed
%ROWCOUNT
Returns the number of rows fetched. It has to be iterated through entire cursor to give exact real count.
SUBSTR returns specific portion of a string and INSTR provides character position in which a pattern is found in a string.
SUBSTR returns string whereas INSTR returns numeric.
What is the parameter mode that can be passed to a procedure?
IN, OUT and INOUT are the modes of parameters that can be passed to a procedure.
What are the different Oracle Database objects?
There are different data objects in Oracle –
Tables – set of elements organized in vertical and horizontal
Views – Virtual table derived from one or more tables
Indexes – Performance tuning method for processing the records
Synonyms – Alias name for tables
Sequences – Multiple users generate unique numbers
Tablespaces – Logical storage unit in Oracle
What are the differences between LOV and List Item?
LOV is property whereas list items are considered as single item. List of items is set to be a collection of list of items. A list item can have only one column, LOV can have one or more columns.
What are privileges and Grants?
Privileges are the rights to execute SQL statements – means Right to connect and connect. Grants are given to the object so that objects can be accessed accordingly. Grants can be provided by the owner or creator of an object.
What is the difference between $ORACLE_BASE and $ORACLE_HOME?
Oracle base is the main or root directory of an oracle whereas ORACLE_HOME is located beneath base folder in which all oracle products reside.
What is the fastest query method to fetch data from the table?
Row can be fetched from table by using ROWID. Using ROW ID is the fastest query method to fetch data from the table.
What is the maximum number of triggers that can be applied to a single table?
12 is the maximum number of triggers that can be applied to a single table.
How to display employee records who gets more salary than the average salary in the department?
This can be done by this query –
Select * from employee where salary>(select avg(salary) from dept, employee where dept.deptno = employee.deptno;
1
Select * from employee where salary>(select avg(salary) from dept, employee where dept.deptno = employee.deptno;
A GROUP BY clause can be used in select statement where it will collect data across multiple records and group the results by one or more columns.