What Is A Private Synonym?
Only its owner can access a private synonym.
What Are The Types Of Synonyms?
There are two types of synonyms private and public.
What Is A Synonym?
A synonym is an alias for a table, view, sequence or program unit.
What Is The Significance Of Having Storage Clause?
We can plan the storage for a table as how much initial extents are required, how much can be extended next, how much % should leave free for managing row updating, etc.,
Which Parameter In Storage Clause Will Reduce Number Of Rows Per Block?
PCTFREE parameter
Row size also reduces no of rows per block.
What Is Meant By Free Extent?
A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its extents are reallocated and are marked as free.
How Will You Force Database To Use Particular Rollback Segment?
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.
List The Optional Flexible Architecture (ofa) Of Oracle Database? How Can We Organize The Tablespaces In Oracle Database To Have Maximum Performance?
SYSTEM – Data dictionary tables.
DATA - Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES – Indexes for Standard operational tables.
INDEXES1 – Indexes of static tables used for standard operations.
TOOLS – Tools table.
TOOLS1 – Indexes for tools table.
RBS – Standard Operations Rollback Segments,
RBS1,RBS2 – Additional/Special Rollback segments.
TEMP – Temporary purpose tablespace
TEMP_USER – Temporary tablespace for users.
USERS – User tablespace.
How Will You Swap Objects Into A Different Table Space For An Existing Database?
- Export the user
- Perform import using the command imp system/manager file=export.dmp indexfile=newrite.sql. This will create all definitions into newfile.sql.
- Drop necessary objects.
- Run the script newfile.sql after altering the tablespaces.
- Import from the backup for the necessary objects.
What Is An Index? How It Is Implemented In Oracle Database?
An index is a database structure used by the server to have direct access of a row in a table. An index is automatically created when a unique of primary key constraint clause is specified in create table command
What Is A Schema?
The set of objects owned by user account is called the schema.
What Is Parallel Server?
Multiple instances accessing the same database (only in multi-CPU environments)
What Is A Database Instance? Explain.
A database instance (Server) is a set of memory structure and background processes that access a set of database files. The processes can be shared by all of the users.
The memory structure that is used to store the most queried data from database. This helps up to improve database performance by decreasing the amount of I/O performed against data file.
What Is The Use Of Control File?
When an instance of an Oracle database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.
What is BLOB datatype?
A BLOB data type is a varying length binary string which is used to store two gigabytes memory. Length should be specified in Bytes for BLOB.
How do we represent comments in Oracle?
Comments in Oracle can be represented in two ways –
Two dashes(–) before beginning of the line – Single statement
/*—— */ is used to represent it as comments for block of statement
Difference between varchar and varchar2 data types?
Varchar can store upto 2000 bytes and varchar2 can store upto 4000 bytes. Varchar will occupy space for NULL values and Varchar2 will not occupy any space. Both are differed with respect to space.
In which language Oracle has been developed?
Oracle has been developed using C Language.
What is RAW datatype?
RAW datatype is used to store values in binary data format. The maximum size for a raw in a table in 32767 bytes.
What is the use of NVL function?
The NVL function is used to replace NULL values with another or given value. Example is –
NVL(Value, replace value)
What is DML?
Data Manipulation Language (DML) is used to access and manipulate data in the existing objects. DML statements are insert, select, update and delete and it won’t implicitly commit the current transaction.
What is key preserved table?
A table is set to be key preserved table if every key of the table can also be the key of the result of the join. It guarantees to return only one copy of each row from the base table.
What is WITH CHECK OPTION?
The WITH CHECK option clause specifies check level to be done in DML statements. It is used to prevent changes to a view that would produce results that are not included in the sub query.
What is the use of Aggregate functions in Oracle?
Aggregate function is a function where values of multiple rows or records are joined together to get a single value output. Common aggregate functions are –
Average
Count
Sum
How can we view last record added to a table?
Last record can be added to a table and this can be done by –
Select * from (select * from employees order by rownum desc) where rownum<2;
1
Select * from (select * from employees order by rownum desc) where rownum<2;
What is the data type of DUAL table?
The DUAL table is a one-column table present in oracle database. The table has a single VARCHAR2(1) column called DUMMY which has a value of ‘X’.
What is difference between Cartesian Join and Cross Join?
There are no differences between the join. Cartesian and Cross joins are same. Cross join gives cartesian product of two tables – Rows from first table is multiplied with another table which is called cartesian product.
Cross join without where clause gives Cartesian product.
Only its owner can access a private synonym.
What Are The Types Of Synonyms?
There are two types of synonyms private and public.
What Is A Synonym?
A synonym is an alias for a table, view, sequence or program unit.
What Is The Significance Of Having Storage Clause?
We can plan the storage for a table as how much initial extents are required, how much can be extended next, how much % should leave free for managing row updating, etc.,
Which Parameter In Storage Clause Will Reduce Number Of Rows Per Block?
PCTFREE parameter
Row size also reduces no of rows per block.
What Is Meant By Free Extent?
A free extent is a collection of continuous free blocks in tablespace. When a segment is dropped its extents are reallocated and are marked as free.
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How Will You Force Database To Use Particular Rollback Segment?
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.
List The Optional Flexible Architecture (ofa) Of Oracle Database? How Can We Organize The Tablespaces In Oracle Database To Have Maximum Performance?
SYSTEM – Data dictionary tables.
DATA - Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES – Indexes for Standard operational tables.
INDEXES1 – Indexes of static tables used for standard operations.
TOOLS – Tools table.
TOOLS1 – Indexes for tools table.
RBS – Standard Operations Rollback Segments,
RBS1,RBS2 – Additional/Special Rollback segments.
TEMP – Temporary purpose tablespace
TEMP_USER – Temporary tablespace for users.
USERS – User tablespace.
How Will You Swap Objects Into A Different Table Space For An Existing Database?
- Export the user
- Perform import using the command imp system/manager file=export.dmp indexfile=newrite.sql. This will create all definitions into newfile.sql.
- Drop necessary objects.
- Run the script newfile.sql after altering the tablespaces.
- Import from the backup for the necessary objects.
An index is a database structure used by the server to have direct access of a row in a table. An index is automatically created when a unique of primary key constraint clause is specified in create table command
What Is A Schema?
The set of objects owned by user account is called the schema.
What Is Parallel Server?
Multiple instances accessing the same database (only in multi-CPU environments)
What Is A Database Instance? Explain.
A database instance (Server) is a set of memory structure and background processes that access a set of database files. The processes can be shared by all of the users.
The memory structure that is used to store the most queried data from database. This helps up to improve database performance by decreasing the amount of I/O performed against data file.
What Is The Use Of Control File?
When an instance of an Oracle database is started, its control file is used to identify the database and redo log files that must be opened for database operation to proceed. It is also used in database recovery.
What is BLOB datatype?
A BLOB data type is a varying length binary string which is used to store two gigabytes memory. Length should be specified in Bytes for BLOB.
How do we represent comments in Oracle?
Comments in Oracle can be represented in two ways –
Two dashes(–) before beginning of the line – Single statement
/*—— */ is used to represent it as comments for block of statement
Difference between varchar and varchar2 data types?
Varchar can store upto 2000 bytes and varchar2 can store upto 4000 bytes. Varchar will occupy space for NULL values and Varchar2 will not occupy any space. Both are differed with respect to space.
In which language Oracle has been developed?
Oracle has been developed using C Language.
What is RAW datatype?
RAW datatype is used to store values in binary data format. The maximum size for a raw in a table in 32767 bytes.
What is the use of NVL function?
The NVL function is used to replace NULL values with another or given value. Example is –
NVL(Value, replace value)
What is DML?
Data Manipulation Language (DML) is used to access and manipulate data in the existing objects. DML statements are insert, select, update and delete and it won’t implicitly commit the current transaction.
What is key preserved table?
A table is set to be key preserved table if every key of the table can also be the key of the result of the join. It guarantees to return only one copy of each row from the base table.
What is WITH CHECK OPTION?
The WITH CHECK option clause specifies check level to be done in DML statements. It is used to prevent changes to a view that would produce results that are not included in the sub query.
What is the use of Aggregate functions in Oracle?
Aggregate function is a function where values of multiple rows or records are joined together to get a single value output. Common aggregate functions are –
Average
Count
Sum
How can we view last record added to a table?
Last record can be added to a table and this can be done by –
Select * from (select * from employees order by rownum desc) where rownum<2;
1
Select * from (select * from employees order by rownum desc) where rownum<2;
What is the data type of DUAL table?
The DUAL table is a one-column table present in oracle database. The table has a single VARCHAR2(1) column called DUMMY which has a value of ‘X’.
What is difference between Cartesian Join and Cross Join?
There are no differences between the join. Cartesian and Cross joins are same. Cross join gives cartesian product of two tables – Rows from first table is multiplied with another table which is called cartesian product.
Cross join without where clause gives Cartesian product.