Oracle : Invisible columns (12c New Feature)

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Invisible columns (12c New Feature)

 

Oracle 12C has introduced the concept of invisible columns. The idea of invisible columns is to hide the some columns in a table.

It can provide the security for crucial information maintained columns in a table.

It is similar to the view in prior versions of Oracle.  Before Oracle version 12c we used views to hide some columns in a table while displaying data to the end users.

User can defined invisible columns during creation of table with the CREATE TABLE command.

User can modify the existing table columns to invisible with the ALTER command. By default table columns are always visible.

Invisible columns are still available for indexing and can be used for cost based optimizer.

If column is modified to invisible and later it changing it to visible the column order changes.

When you change an invisible column to visible then the COL# assigned value will be change to the highest (make it the end column of the table).

The order of the columns is changing in this case so we can’t go for  explicit method wile inserting the data. We try to use the implicit method.

If the application uses ” SELECT * ” or  ” INSERT ”  without column names it might stop the task.

 

 

Once a table’s column is set to invisible, the following key statements will not work for the invisible column.

  • SQL Statement SELECT * FROM
  • SQL*Plus Command DESCRIBE
  • PL/SQL variable declaration %ROWTYPE

 

The Following demo will help u to understand the invisible columns concept.

Creation of Normal Table.

 

 

 

 ADDING COLUMNS IN B/W EXISTING COLUMNS BY USING INVISIBLE UTILITY 

 

 

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Note: Please test scripts in Non Prod before trying in Production.
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