What is data block?

What is data block?
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1 Answer

Answer :

Oracle database's data is stored in data blocks. One data block
corresponds to a specific number of bytes of physical database space
on disk.
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Related questions

Explain the difference between a data block, an extent and a segment.

Description : Explain the difference between a data block, an extent and a segment.

Last Answer : A data block is the smallest unit of logical storage for a database object. As objects grow they take chunks of additional storage that are composed of contiguous data blocks. These groupings ... that an object takes when grouped together are considered the segment of the database object.

How to define data block size?

Description : How to define data block size?

Last Answer : A data block size is specified for each Oracle database when the database is created. A database users and allocated free database space in Oracle data blocks. Block size is specified in init.ora file and cannot be changed latter.

How to define Data Block size ?

Description : How to define Data Block size ?

Last Answer : A data block size is specified for each ORACLE database when the database is created. A database users and allocated free database space in ORACLE datablocks. Block size is specified in INIT.ORA file and can’t be changed latter.

Can object group have a block?

Description : Can object group have a block?

Last Answer : Yes , object group can have block as well as program units.

What are the Various Block Coordination Properties

Description : What are the Various Block Coordination Properties

Last Answer : The various Block Coordination Properties are a) Immediate Default Setting. The Detail records are shown when the Master Record are shown. b) Deffered with Auto Query Oracle Forms defer fetching the ... No Auto Query The operator must navigate to the detail block and explicitly execute a query

What are the different types of Coordinations of the Master with the Detail block?

Description : What are the different types of Coordinations of the Master with the Detail block?

Last Answer : POPULATE_GROUP(function) POPULATE_GROUP_WITH_QUERY(function) SET_GROUP_CHAR_CELL(procedure) SET_GROUPCELL(procedure) SET_GROUP_NUMBER_CELL(procedure)

What are the components of a PL/SQL block ?

Description : What are the components of a PL/SQL block ?

Last Answer : A set of related declarations and procedural statements is called block.

What are the components of a PL/SQL Block ?

Description : What are the components of a PL/SQL Block ?

Last Answer : Declarative part, Executable part and Exception part.Datatypes PL/SQL

Explain how procedures and functions are called in a PL/SQL block ?

Description : Explain how procedures and functions are called in a PL/SQL block ?

Last Answer : Function is called as part of an expression. sal := calculate_sal ('a822'); procedure is called as a PL/SQL statement calculate_bonus ('A822');

Explain types of Block in forms4.0?

Description : Explain types of Block in forms4.0?

Last Answer : Base table Blocks. Control Blocks. 1. A base table block is one that is associated with a specific database table or view. 2. A control block is a block that is not associated with a database table. ITEMS

List the system variables related in Block and Field?

Description : List the system variables related in Block and Field?

Last Answer : 1. System.block_status 2. System.current_block 3. System.current_field 4. System.current_value 5. System.cursor_block 6. System.cursor_field 7. System.field_status.

Committed block sometimes refer to a BASE TABLE ?

Description : Committed block sometimes refer to a BASE TABLE ?

Last Answer : False

What does an on-clear-block Trigger fire?

Description : What does an on-clear-block Trigger fire?

Last Answer : It fires just before SQL * forms the current block.

What is Post-Block is a. ???

Description : What is Post-Block is a. ???

Last Answer : a. Navigational Trigger. b. Key trigger c. Transaction Trigger.

Can we use GO-BLOCK package in a pre-field trigger ?

Description : Can we use GO-BLOCK package in a pre-field trigger ?

Last Answer : No

Give the sequence in which triggers fired during insert operations, when the following 3 triggers are defined at the same block level ?

Description : Give the sequence in which triggers fired during insert operations, when the following 3 triggers are defined at the same block level ?

Last Answer : a. ON-INSERT b. POST-INSERT c. PRE-INSERT

How does Space allocation table place within a block ?

Description : How does Space allocation table place within a block ?

Last Answer : Each block contains entries as follows Fixed block header Variable block header Row Header,row date (multiple rows may exists) PCTEREE (% of free space for row updation in future)

Which parameter in Storage clause will reduce no. of rows per block?

Description : Which parameter in Storage clause will reduce no. of rows per block?

Last Answer : PCTFREE parameter Row size also reduces no of rows per block.

What are the two phases of block coordination?

Description : What are the two phases of block coordination?

Last Answer : There are two phases of block coordination: the clear phase and the population phase. During, the clear phase, Oracle Forms navigates internally to the detail block and flushes the obsolete ... with the new master record. These operations are accomplished through the execution of triggers.

What database block size should I use? (for DBA)

Description : What database block size should I use? (for DBA)

Last Answer : Oracle recommends that your database block size match, or be multiples of your operating system block size. One can use smaller block sizes, but the performance cost is significant. Your choice should ... 8K. This is because volume manager products use 8K blocks (and this is not configurable).

What is Oracle Block? Can two Oracle Blocks have the same address?

Description : What is Oracle Block? Can two Oracle Blocks have the same address?

Last Answer : Oracle formats the database files into a number of Oracle blocks when they are first created-making it easier for the RDBMS software to manage the files and easier to read data into the memory areas ... at 1. Two blocks can have the same block address if they are in different database files.

Can a repeating frame be created without a data group as a base?

Description : Can a repeating frame be created without a data group as a base?

Last Answer : No

Can one resize tablespaces and data files? (for DBA)

Description : Can one resize tablespaces and data files? (for DBA)

Last Answer : One can manually increase or decrease the size of a datafile from Oracle 7.2 using the command. ALTER DATABASE DATAFILE 'filename2' RESIZE 100M; Because you can change the ... UNLIMITED DEFAULT STORAGE (INITIAL 10240 NEXT 10240 MINEXTENTS 1 MAXEXTENTS UNLIMITED PCTINCREASE 0) ONLINE PERMANENT;

What view would you use to look at the size of a data file?

Description : What view would you use to look at the size of a data file?

Last Answer : DBA_DATA_FILES

How do you resize a data file?

Description : How do you resize a data file?

Last Answer : ALTER DATABASE DATAFILE RESIZE ;

How do you add a data file to a tablespace

Description : How do you add a data file to a tablespace

Last Answer : ALTER TABLESPACE ADD DATAFILE SIZE

Give the two types of tables involved in producing a star schema and the type of data they hold.

Description : Give the two types of tables involved in producing a star schema and the type of data they hold.

Last Answer : Fact tables and dimension tables. A fact table contains measurements while dimension tables will contain data that will help describe the fact tables.

Is it possible to insert comments into sql statements return in the data model editor?

Description : Is it possible to insert comments into sql statements return in the data model editor?

Last Answer : Yes

The join defined by the default data link is an outer join yes or no?

Description : The join defined by the default data link is an outer join yes or no?

Last Answer : Yes

Can a field be used in a report without it appearing in any data group?

Description : Can a field be used in a report without it appearing in any data group?

Last Answer : Yes

For a field in a repeating frame, can the source come from the column which does not exist in the data group which forms the base for the frame?

Description : For a field in a repeating frame, can the source come from the column which does not exist in the data group which forms the base for the frame?

Last Answer : Yes

What are the characteristics of data files?

Description : What are the characteristics of data files?

Last Answer : A data file can be associated with only one database. Once created a data file can't change size. One or more data files form a logical unit of database storage called a tablespace.

What is a data segment?

Description : What is a data segment?

Last Answer : Each non-clustered table has a data segment. All of the table's data is stored in the extents of its data segment. Each cluster has a data segment. The data of every table in the cluster is stored in the cluster's data segment.

Physical Storage of the Data

Description : Physical Storage of the Data

Last Answer : The finest level of granularity of the data base are the data blocks. Data Block :: One Data Block correspond to specific number of physical database space Extent :: Extent is the number of ... Index has index segment that stores data c) Roll Back Segment :: Temporarily store 'undo' information

Table Space,Data Files,Parameter File, Control Files

Description : Table Space,Data Files,Parameter File, Control Files

Last Answer : Table Space :: The table space is useful for storing the data in the database.When a database is created two table spaces are created. a) System Table space :: This data file stores all the tables ... They contain the Db name, name and location of dbs, data files ,redo log files and time stamp.

What are the data types allowed in a table ?

Description : What are the data types allowed in a table ?

Last Answer : CHAR,VARCHAR2,NUMBER,DATE,RAW,LONG and LONG RAW.

Where the integrity constraints are stored in Data Dictionary ?

Description : Where the integrity constraints are stored in Data Dictionary ?

Last Answer : The integrity constraints are stored in USER_CONSTRAINTS.

Difference between NO DATA FOUND and %NOTFOUND?

Description : Difference between NO DATA FOUND and %NOTFOUND?

Last Answer : NO DATA FOUND is an exception raised only for the SELECT....INTO statements when the where clause of the querydoes not match any rows. When the where clause of the explicit cursor does not match any rows the %NOTFOUND attribute is set to TRUE instead.

What should be the return type for a cursor variable.Can we use a scalar data type as return type?

Description : What should be the return type for a cursor variable.Can we use a scalar data type as return type?

Last Answer : The return type for a cursor must be a record type.It can be declared explicitly as a user-defined or %ROWTYPE can be used. eg TYPE t_studentsref IS REF CURSOR RETURN students%ROWTYPE

It is possible to use raw devices as data files and what is the advantages over file. system files ?

Description : It is possible to use raw devices as data files and what is the advantages over file. system files ?

Last Answer : Yes. The advantages over file system files. I/O will be improved because Oracle is bye-passing the kernnel which writing into disk. Disk Corruption will be very less.

What are the two ways by which data can be generated for a parameters list of values?

Description : What are the two ways by which data can be generated for a parameters list of values?

Last Answer : 1. Using static values. 2. Writing select statement.

Why is it preferable to create a fewer no. of queries in the data model?

Description : Why is it preferable to create a fewer no. of queries in the data model?

Last Answer : Because for each query, report has to open a separate cursor and has to rebind, execute and fetch data.

Atleast how many set of data must a data model have before a data model can be base on it?

Description : Atleast how many set of data must a data model have before a data model can be base on it?

Last Answer : Four

Can you pass data parameters to forms?

Description : Can you pass data parameters to forms?

Last Answer : No

Do user parameters appear in the data modal editor in 2.5?

Description : Do user parameters appear in the data modal editor in 2.5?

Last Answer : No

Does a grouping done for objects in the layout editor affect the grouping done in the data model editor?

Description : Does a grouping done for objects in the layout editor affect the grouping done in the data model editor?

Last Answer : No.

Does Oracle write to data files in begin/hot backup mode? (for DBA

Description : Does Oracle write to data files in begin/hot backup mode? (for DBA

Last Answer : Oracle will stop updating file headers, but will continue to write data to the database files even if a tablespace is in backup mode.In backup mode, Oracle will write out complete changed blocks ... ). Because of this, one should notice increased log activity and archiving during on-line backups.

What is the basic data structure that is required for creating an LOV?

Description : What is the basic data structure that is required for creating an LOV?

Last Answer : Record Group.

If two groups are not linked in the data model editor, What is the hierarchy between them?

Description : If two groups are not linked in the data model editor, What is the hierarchy between them?

Last Answer : Two group that is above are the left most rank higher than the group that is to right or below it.

When do you use data parameter type?

Description : When do you use data parameter type?

Last Answer : When the value of a data parameter being passed to a called product is always the name of the record group defined in the current form. Data parameters are used to pass data to produts invoked with the run_product built-in subprogra