| max no. of columns [message #207544] |
Wed, 06 December 2006 00:12  |
amit_vass2000
Messages: 52
Registered: December 2006
Location: Delhi
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what maximum number of columns can be create in a table? It is a interview question. Plz reply me. Thanks
Amit Vashishtha
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| Re: max no. of columns [message #207563 is a reply to message #207544] |
Wed, 06 December 2006 01:03  |
amit_vass2000
Messages: 52
Registered: December 2006
Location: Delhi
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FROM INFOCENTER.SYBASE.COM SITE I FOUND THIS MATTER.
Number of columns and size
The maximum number of columns you can create in a table is:
1024 for fixed-length columns in both all-pages-locked (APL) and data-only- locked (DOL) tables
254 for variable-length columns in an APL table
1024 for variable-length columns in an DOL table
The maximum size of a column depends on:
Whether the table includes any variable- or fixed-length columns.
The logical page size of the database. For example, in a database with 2K logical pages, the maximum size of a column in an APL table can be as large as a single row, about 1962 bytes, less the row format overheads. Similarly, for a 4K page, the maximum size of a column in a APL table can be as large as 4010 bytes, less the row format overheads. See Table 0-1 for more information.
If you attempt to create a table with a fixed-length column that is greater than the limits of the logical page size, create table issues an error message.
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| Re: max no. of columns [message #207568 is a reply to message #207563] |
Wed, 06 December 2006 01:21 |
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Littlefoot
Messages: 21823
Registered: June 2005
Location: Croatia, Europe
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Senior Member
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You showed us what SYBASE says about it.
This is what Oracle says:| Quote: | ORA-01792: maximum number of columns in a table or view is 1000
Cause: An attempt was made to create a table or view with more than 1000 columns, or to add more columns to a table or view which pushes it over the maximum allowable limit of 1000. Note that unused columns in the table are counted toward the 1000 column limit.
Action: If the error is a result of a CREATE command, then reduce the number of columns in the command and resubmit. If the error is a result of an ALTER TABLE command, then there are two options: 1) If the table contained unused columns, remove them by executing ALTER TABLE DROP UNUSED COLUMNS before adding new columns; 2) Reduce the number of columns in the command and resubmit.
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