What is the Difference between a post query and a pre query

What is the Difference between a post query and a pre query
by

1 Answer

Answer :

A post query will fire for every row that is fetched but the pre query will
fire only once.
by

Related questions

A query fetched 10 records How many times does a PRE- QUERY Trigger and POST-QUERY Trigger will get executed ?

Description : A query fetched 10 records How many times does a PRE-QUERY Trigger and POST-QUERY Trigger will get executed ?

Last Answer : PRE-QUERY fires once. POST-QUERY fires 10 times.

What is a difference between pre-select and pre-query?

Description : What is a difference between pre-select and pre-query?

Last Answer : Fires during the execute query and count query processing after oracle forms constructs the select statement to be issued, but before the statement is actually issued. The pre-query trigger fires ... the query criteria in enter query mode.Pre-query trigger fires before pre-select trigger.

When is PRE-QUERY trigger executed ?

Description : When is PRE-QUERY trigger executed ?

Last Answer : When Execute-query or count-query Package procedures are invoked.

What is the Difference between a post query and a pre query?

Description : What is the Difference between a post query and a pre query?

Last Answer : A post query will fire for every row that is fetched but the pre query will fire only once.

If the maximum record retrieved property of the query is set to 10 then a summary value will be calculated?

Description : If the maximum record retrieved property of the query is set to 10 then a summary value will be calculated?

Last Answer : Only for 10 records.

What is a Query Record Group?

Description : What is a Query Record Group?

Last Answer : A query record group is a record group that has an associated SELECT statement. The columns in a query record group derive their default names, data types, had lengths from the database columns ... rows retrieved by the query associated with that record group. What is a Non Query Record Group?

How you will avoid your query from using indexes?

Description : How you will avoid your query from using indexes?

Last Answer : SELECT * FROM emp Where emp_no+' '=12345; i.e you have to concatenate the column name with space within codes in the where condition. SELECT /*+ FULL(a) */ ename, emp_no from emp where emp_no=1234; i.e using HINTS

Suppose a customer table is having different columns like customer no, payments.What will be the query to select top three max payments?

Description : Suppose a customer table is having different columns like customer no, payments.What will be the query to select top three max payments?

Last Answer : SELECT customer_no, payments from customer C1 WHERE 3

What is correlated sub-query ?

Description : What is correlated sub-query ?

Last Answer : Correlated sub query is a sub query which has reference to the main query.

There is a % sign in one field of a column. What will be the query to find it?

Description : There is a % sign in one field of a column. What will be the query to find it?

Last Answer : '' Should be used before '%'.

How you will avoid duplicating records in a query?

Description : How you will avoid duplicating records in a query?

Last Answer : By using DISTINCT

My query was fine last week and now it is slow. Why? (for DBA

Description : My query was fine last week and now it is slow. Why? (for DBA

Last Answer : The likely cause of this is because the execution plan has changed. Generate a current explain plan of the offending query and compare it to a previous one that was taken when the query was ... the plan should be? Run the query with hints to see if this produces the required performance.

Why query fails sometimes ?

Description : Why query fails sometimes ?

Last Answer : Rollback segment dynamically extent to handle larger transactions entry loads. A single transaction may wipeout all available free space in the Rollback Segment Tablespace. This prevents other user using Rollback segments.

Where is the external query executed at the client or the server?

Description : Where is the external query executed at the client or the server?

Last Answer : At the server.

How is it possible to select generate a select set for the query in the query property sheet?

Description : How is it possible to select generate a select set for the query in the query property sheet?

Last Answer : By using the tables/columns button and then specifying the table and the column names.

Is it possible to modify an external query in a report which contains it?

Description : Is it possible to modify an external query in a report which contains it?

Last Answer : No.

If a parameter is used in a query without being previously defined, what diff. exist betw. report 2.0 and 2.5 when the query is applied?

Description : If a parameter is used in a query without being previously defined, what diff. exist betw. report 2.0 and 2.5 when the query is applied?

Last Answer : While both reports 2.0 and 2.5 create the parameter, report 2.5 gives a message that a bind parameter has been created.

What is a query?

Description : What is a query?

Last Answer : A query with respect to DBMS relates to user commands that are used to interact with a data base. The query language can be classified into data definition language and data manipulation language.

What is meant by query optimization?

Description : What is meant by query optimization?

Last Answer : The phase that identifies an efficient execution plan for evaluating a query that has the least estimated cost is referred to as query optimization.

What is Query evaluation engine?

Description : What is Query evaluation engine?

Last Answer : It executes low-level instruction generated by compiler.

What are the pre requisites ?

Description : What are the pre requisites ?

Last Answer : I. to modify data type of a column ? ii. to add a column with NOT NULL constraint ? To Modify the datatype of a column the column must be empty. to add a column with NOT NULL constrain, the table must be empty.

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

What is the difference between ON-VALIDATE-FIELD trigger and a POST-CHANGE trigger ?

Description : What is the difference between ON-VALIDATE-FIELD trigger and a POST-CHANGE trigger ?

Last Answer : When you changes the Existing value to null, the On-validate field trigger will fire post change trigger will not fire. At the time of execute- query post-change trigger will fire, on-validate field trigger will not fire.

what are difference between post database commit and post-form commit?

Description : what are difference between post database commit and post-form commit?

Last Answer : Post-form commit fires once during the post and commit transactions process, after the database commit occurs. The post-form-commit trigger fires after inserts, updates and deletes have ... The post-database-commit trigger fires after oracle forms issues the commit to finalized transactions.

What is Post-Block is a. ???

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

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

Difference between SUBSTR and INSTR ?

Description : Difference between SUBSTR and INSTR ?

Last Answer : INSTR (String1,String2(n,(m)),INSTR returns the position of the mth occurrence of the string 2 instring1. The search begins from nth position of string1.SUBSTR (String1 n,m)SUBSTR returns a character string of size m in string1, starting from nth position of string1.

What is the difference between DBFile Sequential and Scattered Reads?(for DBA

Description : What is the difference between DBFile Sequential and Scattered Reads?(for DBA

Last Answer : Both "db file sequential read" and "db file scattered read" events signify time waited for I/O read requests to complete. Time is reported in 100's of a second for Oracle 8i releases and below, ... v_$system_event b where a.event = 'db file sequential read' and b.event = 'db file scattered read';

What is the difference between static and dynamic lov

Description : What is the difference between static and dynamic lov

Last Answer : The static lov contains the predetermined values while the dynamic lov contains values that come at run time

What is the difference between NAME_IN and COPY ?

Description : What is the difference between NAME_IN and COPY ?

Last Answer : Copy is package procedure and writes values into a field. Name in is a package function and returns the contents of the variable to which you apply.

What is the difference between restoring and recovering? (for DBA

Description : What is the difference between restoring and recovering? (for DBA

Last Answer : Restoring involves copying backup files from secondary storage (backup media) to disk. This can be done to replace damaged files or to copy/move a database to a new location. Recovery is the process ... as SYSDBA Sql> RECOVER DATABASE UNTIL TIME '2001-03-06:16:00:00' USING BACKUP CONTROLFILE;

What is the difference between online and offline backups? (for DBA

Description : What is the difference between online and offline backups? (for DBA

Last Answer : A hot backup is a backup performed while the database is online and available for read/write. Except for Oracle exports, one can only do on- line backups when running in ARCHIVELOG mode. A cold backup is a backup performed while the database is off-line and unavailable to its users.

What is the difference between the SQL*Loader and IMPORT utilities?

Description : What is the difference between the SQL*Loader and IMPORT utilities?

Last Answer : These two Oracle utilities are used for loading data into the database. The difference is that the import utility relies on the data being produced by another Oracle utility EXPORT while the SQL* ... from different data sources just so long as it conforms to ASCII formatted or delimited files.

What is the difference between a TEMPORARY tablespace and a PERMANENT tablespace?

Description : What is the difference between a TEMPORARY tablespace and a PERMANENT tablespace?

Last Answer : A temporary tablespace is used for temporary objects such as sort structures while permanent tablespaces are used to store those objects meant to be used as the true objects of the database.

Explain the difference between a FUNCTION, PROCEDURE and PACKAGE.

Description : Explain the difference between a FUNCTION, PROCEDURE and PACKAGE.

Last Answer : A function and procedure are the same in that they are intended to be a collection of PL/SQL code that carries a single task. While a procedure does not have to return any ... functions and procedures that are grouped together based on their commonality to a business function or application.

Explain the difference between $ORACLE_HOME and $ORACLE_BASE.

Description : Explain the difference between $ORACLE_HOME and $ORACLE_BASE.

Last Answer : ORACLE_BASE is the root directory for oracle. ORACLE_HOME located beneath ORACLE_BASE is where the oracle products reside.

Explain the difference between ARCHIVELOG mode and NOARCHIVELOG mode and the benefits and disadvantages to each.

Description : Explain the difference between ARCHIVELOG mode and NOARCHIVELOG mode and the benefits and disadvantages to each.

Last Answer : ARCHIVELOG mode is a mode that you can put the database in for creating a backup of all transactions that have occurred in the database so that you can recover to any point in time. ... having to write transactions to an archive log and thus increases the performance of the database slightly.

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.

Explain the difference between a hot backup and a cold backup and the benefits associated with each.

Description : Explain the difference between a hot backup and a cold backup and the benefits associated with each.

Last Answer : A hot backup is basically taking a backup of the database while it is still up and running and it must be in archive log mode. A cold backup is taking a backup of the database while it is ... and thus there will be a slight performance gain as the database is not cutting archive logs to disk.

What is the difference between deleting and truncating of tables

Description : What is the difference between deleting and truncating of tables

Last Answer : Deleting a table will not remove the rows from the table but entry is there in the database dictionary and it can be retrieved But truncating a table deletes it completely and it cannot be retrieved.

What is the difference between candidate key, unique key and primary key

Description : What is the difference between candidate key, unique key and primary key

Last Answer : Candidate keys are the columns in the table that could be the primary keys and the primary key is the key that has been selected to identify the rows. Unique key is also useful for identifying the distinct rows in the table.)

What is difference between CHAR and VARCHAR2 ? What is the maximum SIZE allowed for each type ?

Description : What is difference between CHAR and VARCHAR2 ? What is the maximum SIZE allowed for each type ?

Last Answer : CHAR pads blank spaces to the maximum length. VARCHAR2 does not pad blank spaces. For CHAR it is 255 and 2000 for VARCHAR2.

What is difference between TRUNCATE & DELETE ?

Description : What is difference between TRUNCATE & DELETE ?

Last Answer : TRUNCATE commits after deleting entire table i.e., can not be rolled back. Database triggers do not fire on TRUNCATEDELETE allows the filtered deletion. Deleted records can be rolled back or committed.Database triggers fire on DELETE.

What is difference between UNIQUE and PRIMARY KEY constraints?

Description : What is difference between UNIQUE and PRIMARY KEY constraints?

Last Answer : A table can have only one PRIMARY KEY whereas there can be any number of UNIQUE keys. The columns that compose PK are automatically define NOT NULL, whereas a column that compose a UNIQUE is not automatically defined to be mandatory must also specify the column is NOT NULL.

Difference between database triggers and form triggers?

Description : Difference between database triggers and form triggers?

Last Answer : Data base trigger(DBT) fires when a DML operation is performed on a data base table. Form trigger(FT) Fires when user presses a key or navigates between fields on the screen -Can be row ... other database triggers to fire.Can cause other database triggers to fire, but not other form triggers.

Difference between procedure and function.?

Description : Difference between procedure and function.?

Last Answer : Functions are named PL/SQL blocks that return a value and can be called with arguments procedure a named block that can be called with parameter. A procedure all is a PL/SQL statement by itself, while a Function call is called as part of an expression.

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.

Difference between an implicit & an explicit cursor.?

Description : Difference between an implicit & an explicit cursor.?

Last Answer : only one row. However,queries that return more than one row you must declare an explicit cursor or use a cursor FOR loop. Explicit cursor is a cursor in which the cursor name is explicitly ... statements An implicit cursor is used to process INSERT, UPDATE, DELETE and single row SELECT. .INTO

What is difference between Rename and Alias?

Description : What is difference between Rename and Alias?

Last Answer : Rename is a permanent name given to a table or column whereas Alias is a temporary name given to a table or column which do not exist once the SQL statement is executed.

What is difference between SQL and SQL*PLUS?

Description : What is difference between SQL and SQL*PLUS?

Last Answer : SQL*PLUS is a command line tool where as SQL and PL/SQL language interface and reporting tool. Its a command line tool that allows user to type SQL commands to be executed directly against an Oracle ... SQL*PLUS commands are used to format query result, Set options, Edit SQL commands and PL/SQL.

What is difference between SUBSTR and INSTR?

Description : What is difference between SUBSTR and INSTR?

Last Answer : SUBSTR returns a specified portion of a string eg SUBSTR('BCDEF',4) output BCDE INSTR provides character position in which a pattern is found in a string. eg INSTR('ABC-DC-F','-',2) output 7 (2nd occurence of '-')