What is a View ?

What is a View ?
by

1 Answer

Answer :

A view is a virtual table. Every view has a Query attached to it. (The
Query is a SELECT statement that identifies the columns and rows of
the table(s) the view uses.)
by

Related questions

You have just compiled a PL/SQL package but got errors, how would you view the errors?

Description : You have just compiled a PL/SQL package but got errors, how would you view the errors?

Last Answer : SHOW ERRORS

What view would you use to determine free space in a tablespace?

Description : What view would you use to determine free space in a tablespae?

Last Answer : DBA_FREE_SPACE

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

Can a view be updated/inserted/deleted? If Yes under what conditions ?

Description : Can a view be updated/inserted/deleted? If Yes under what conditions ?

Last Answer : A View can be updated/deleted/inserted if it has only one base table if the view is based on columns from one or more tables then insert, update and delete is not possible.

If a View on a single base table is manipulated will the changes be reflected on the base table ?

Description : If a View on a single base table is manipulated will the changes be reflected on the base table ?

Last Answer : If changes are made to the tables which are base tables of a view will the changes be reference on the view.

What are the advantages of VIEW ?

Description : What are the advantages of VIEW ?

Last Answer : To protect some of the columns of a table from other users.To hide complexity of a query.To hide complexity of calculations.

What is a view ?

Description : What is a view ?

Last Answer : A view is stored procedure based on one or more tables, it’s a virtual table.

What is a canvas-view?

Description : What is a canvas-view?

Last Answer : A canvas-view is the background object on which you layout the interface items (text-items, check boxes, radio groups, and so on.) and boilerplate objects that operators see and interact with as they ... assigned to a specific canvas. Each canvas, in term, must be displayed in a specific window.

What is the content view and stacked view?

Description : What is the content view and stacked view?

Last Answer : A content view is the "Base" view that occupies the entire content pane of the window in which it is displayed. A stacked view differs from a content canvas view in that it is not the base view for the window to which it is assigned

Do a view contain data?

Description : Do a view contain data?

Last Answer : Views do not contain or store data.

Can you have more than one content canvas view attached with a window?

Description : Can you have more than one content canvas view attached with a window?

Last Answer : Yes. Each window you create must have atleast one content canvas view assigned to it. You can also create a window that has manipulated content canvas view. At run time only one of the content canvas views assign to a window is displayed at a time.

How does one get the view definition of fixed views/tables?

Description : How does one get the view definition of fixed views/tables?

Last Answer : Query v$fixed_view_definition. Example: SELECT * FROM v$fixed_view_definition WHERE view_name='V$SESSION';

Can a view based on another view?

Description : Can a view based on another view?

Last Answer : Yes.

Do View contain Data ?

Description : Do View contain Data ?

Last Answer : Views do not contain or store data.

Can a View based on another View ?

Description : Can a View based on another View ?

Last Answer : Yes.

What is an Oracle view?

Description : What is an Oracle view?

Last Answer : A view is a virtual table. Every view has a query attached to it. (The query is a SELECT statement that identifies the columns and rows of the table(s) the view uses.)

What is VDL (View Definition Language)?

Description : What is VDL (View Definition Language)?

Last Answer : It specifies user views and their mappings to the conceptual schema.

What is a view? How it is related to data independence?

Description : What is a view? How it is related to data independence?

Last Answer : A view may be thought of as a virtual table, that is, a table that does not really exist in its own right but is instead derived from one or more underlying base table. In other ... users from the effects of restructuring and growth in the database. Hence accounts for logical data independence.

What is the difference between a view and a materialized view?

Description : What is the difference between a view and a materialized view?

Last Answer : A view is a select that is executed each time an user accesses to it. A materialized view stores the result of this query in memory for faster access purposes.

How can you view all the current users connected in your database in this moment?

Description : How can you view all the current users connected in your database in this moment?

Last Answer : SELECT COUNT(*),USERNAME FROM V$SESSION GROUP BY USERNAME;

How can you view all the users account in the database?

Description : How can you view all the users account in the database?

Last Answer : SELECT USERNAME FROM DBA_USERS

In which view can you find information about every view and table of oracle dictionary

Description : In which view can you find information about every view and table of oracle dictionary

Last Answer : DICT or DICTIONARY

What does "jumps off the screen" mean?

Description : What does "jumps off the screen" mean?

Last Answer : answer:AMD is a relatively small manufacturer but well established in the industry. In this context, AMD jumps off the screen at the guy doing the research into acquiring companies for ... chip manufacturing division, but AMD is the one that really stands out from an acquisition perspective.

How to add conditions in select statement in oracle?

Description : How to add conditions in select statement in oracle?

Last Answer : Just add the decode

How can I dump an oracle schema to a LOCAL file over a network connection from sqlplus?

Description : How can I dump an oracle schema to a LOCAL file over a network connection from sqlplus?

Last Answer : By connecting and spooling are you excluding the exp/imp commands (or expdb/impdb in 10g)?

What are the two ways to incorporate images into a oracle forms application?

Description : What are the two ways to incorporate images into a oracle forms application?

Last Answer : Boilerplate Images Image_items

Can one export a subset of a table? (for DBA

Description : Can one export a subset of a table? (for DBA

Last Answer : From Oracle8i one can use the QUERY= export parameter to selectively unload a subset of the data from a table. Look at this example: exp scott/tiger tables=emp query=\"where deptno=10\"

What are the types of visual attribute settings?

Description : What are the types of visual attribute settings?

Last Answer : Custom Visual attributes Default visual attributes Named Visual attributes. Window

How does one use the import/export utilities? (for DBA

Description : How does one use the import/export utilities? (for DBA

Last Answer : Look for the "imp" and "exp" executables in your $ORACLE_HOME/bin directory. One can run them interactively, using command line parameters, or using parameter files. Look at the imp/exp parameters ... and export data with the "Schema Manager" GUI that ships with Oracle Enterprise Manager (OEM).

what is a display item?

Description : what is a display item?

Last Answer : Display items are similar to text items but store only fetched or assigned values. Operators cannot navigate to a display item or edit the value it contains.

What is import/export and why does one need it? (for DBA

Description : What is import/export and why does one need it? (for DBA

Last Answer : The Oracle export (EXP) and import (IMP) utilities are used to perform logical database backup and recovery. They are also used to move Oracle data from one machine, database or schema to ... corruption. Ensure that all the data can be read. . Transporting tablespaces between databases . Etc.

Are there any troubleshooting tips for OEM? (for DBA

Description : Are there any troubleshooting tips for OEM? (for DBA

Last Answer : . Create the OEM repository with a user (which will manage the OEM) and store it in a tablespace that does not share any data with other database users. It is a bad practice to create ... successfully. Check the log to see the results of the execution rather than relying on this status.

Where can one get more information about TCL? (for DBA

Description : Where can one get more information about TCL? (for DBA

Last Answer : One can write custom event checking routines for OEM using the TCL (Tool Command Language) language. Check the following sites for more information about TCL: . The Tcl Developer Xchange - ... the OraTCL package . Tom Poindexter's Tcl Page - Oratcl was originally written by Tom Poindexter

How does one start the Oracle Intelligent Agent? (for DBA

Description : How does one start the Oracle Intelligent Agent? (for DBA

Last Answer : One needs to start an OIA (Oracle Intelligent Agent) process on all machines that will to be managed via OEM. For OEM 9i and above:

What is the Oracle Intelligent Agent? (for DBA

Description : What is the Oracle Intelligent Agent? (for DBA

Last Answer : The Oracle Intelligent Agent (OIA) is an autonomous process that needs to run on a remote node in the network to make the node OEM manageable. The Oracle Intelligent Agent is ... events registered in Enterprise Manager; and . Executing tasks associated with jobs submitted to Enterprise Manager.

What are the types of SQL Statement ?

Description : What are the types of SQL Statement ?

Last Answer : Data Definition Language : CREATE,ALTER,DROP,TRUNCATE,REVOKE,NO AUDIT & COMMIT.

How does one backout events and jobs during maintenance slots? (for DBA

Description : How does one backout events and jobs during maintenance slots? (for DBA

Last Answer : Managemnet and data collection activity can be suspended by imposing a blackout. Look at these examples: agentctl start blackout # Blackout the entrire agent agentctl stop blackout # Resume normal monitoring ... management agentctl start blackout -s jobs -d 00:20 # Blackout jobs for 20 minutes

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.

What kind of jobs can one schedule with OEM? (for DBA

Description : What kind of jobs can one schedule with OEM? (for DBA

Last Answer : OEM comes with pre-defined jobs like Export, Import, run OS commands, run sql scripts, SQL*Plus commands etc. It also gives you the flexibility of scheduling custom jobs written with the TCL language.

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.

Should the OEM Console be displayed at all times (when there are scheduled jobs)? (for DBA

Description : Should the OEM Console be displayed at all times (when there are scheduled jobs)? (for DBA

Last Answer : When a job is submitted the agent will confirm the status of the job. When the status shows up as scheduled, you can close down the OEM console. The processing of the job is managed by the OIA ... that OEM will not be able to send e-mail and paging notifications when the Console is not started.

Explain UNION,MINUS,UNION ALL, INTERSECT ?

Description : Explain UNION,MINUS,UNION ALL, INTERSECT ?

Last Answer : INTERSECT returns all distinct rows selected by both queries.MINUS - returns all distinct rows selected by the first query but not by the second.UNION - returns all distinct rows selected by either queryUNION ALL - returns all rows selected by either query, including all duplicates.

WHY USE RMAN ? (for DBA

Description : WHY USE RMAN ? (for DBA

Last Answer : No extra costs Its available free ?RMAN introduced in Oracle 8 it has become simpler with newer versions and easier than user managed backups ?Proper security ?You are 100% sure your ... what need to backed up Knows what is required for recovery Knows what backups are redundant

WHAT IS RMAN ? (for DBA

Description : WHAT IS RMAN ? (for DBA

Last Answer : Recovery Manager is a tool that: manages the process of creating backups and also manages the process of restoring and recovering from them.

What is the basic structure of PL/SQL ?

Description : What is the basic structure of PL/SQL ?

Last Answer : PL/SQL uses block structure as its basic structure. Anonymous blocks or nested blocks can be used in PL/SQL.

What are the two parts of a procedure ?

Description : What are the two parts of a procedure ?

Last Answer : Procedure Specification and Procedure Body.

What are the datatypes a available in PL/SQL ?

Description : What are the datatypes a available in PL/SQL ?

Last Answer : Some scalar data types such as NUMBER, VARCHAR2, DATE, CHAR, LONG, BOOLEAN. Some composite data types such as RECORD & TABLE.

What are the return values of functions SQLCODE and SQLERRM ? What is Pragma EXECPTION_INIT ? Explain the usage ?

Description : What are the return values of functions SQLCODE and SQLERRM ? What is Pragma EXECPTION_INIT ? Explain the usage ?

Last Answer : SQLCODE returns the latest code of the error that has occurred. SQLERRM returns the relevant error message of the SQLCODE.

What is Overloading of procedures ?

Description : What is Overloading of procedures ?

Last Answer : The Same procedure name is repeated with parameters of different datatypes and parameters in different positions, varying number of parameters is called overloading of procedures. e.g. DBMS_OUTPUT put_line

s it possible to set a filter condition in a cross product group in matrix reports?

Description : s it possible to set a filter condition in a cross product group in matrix reports?

Last Answer : No