Please follow the link what Amelia sent you to know in detail, in a nutshell -
Projections are the storage of data of tables for each table, there should be at least one projection (called super projection) for each table you create and may have also other projections based on the requirements but those are duplication of full/part data for some purpose.
These are created automatically when you load the data in the table ( by insert/COPY) although before loading you can create them manually using certain syntax. Also they are created if you use DBD in admintools.
Thank you Prasanta for answering. That means in normal other SQL table all the data will store in Table level , but in vertica it stores in Projects level( this is the major difference). So one clarification i need , that means it will not create projection when we will just create table ??
A single projection is automatically created when the first row of a table is inserted. This projection is called super projection So lets say you create table A, at this point there is no projection for Table A. When you insert your first record into Table A, at this point of time a Super projection will be created for table A automatically.
This was about Super projections. You can also design and create projection manually with a simple SQL CREATE PROJECTION statement.
For more info on Projections in Vertica, you can refer this link
Comments
Projections are the storage of data of tables for each table, there should be at least one projection (called super projection) for each table you create and may have also other projections based on the requirements but those are duplication of full/part data for some purpose.
These are created automatically when you load the data in the table ( by insert/COPY) although before loading you can create them manually using certain syntax. Also they are created if you use DBD in admintools.
That means in normal other SQL table all the data will store in Table level , but in vertica it stores in Projects level( this is the major difference).
So one clarification i need , that means it will not create projection when we will just create table ??
A single projection is automatically created when the first row of a table is inserted. This projection is called super projection
So lets say you create table A, at this point there is no projection for Table A.
When you insert your first record into Table A, at this point of time a Super projection will be created for table A automatically.
This was about Super projections.
You can also design and create projection manually with a simple SQL CREATE PROJECTION statement.
For more info on Projections in Vertica, you can refer this link
http://vertica-forums.com/viewtopic.php?f=6&t=977&p=3023&hilit=projections#p3023
Hope this helps.