Обсуждение: q query about a bug.

Dear

We have a developer doing an application for us using a Postgre Db. One of the items is to export the data into a xml file and then either email or whatever but the ability is there then to import the xml data back into the database. So what happens is that the contents of certain tables are exported into this xml file, and this is all the columns data related to that table. We have checked the XML file and we can verify that all the columns of each table have been exported.

The problem comes in now when the import takes place all the columns data does not appear to be imported and when we asked the developer about this his reply was

There is a known bug in PostGre regarding the number of columns that can be imported…..

Is this a fact and where can I find more information on this?

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Here is the documentation for the copy command:

http://www.postgresql.org/docs/8.3/interactive/sql-copy.html

Here are the limits on columns:

http://www.postgresql.org/docs/8.3/interactive/sql-createtable.html

In particular:

“A table cannot have more than 1600 columns. (In practice, the effective limit is usually lower because of tuple-length constraints.) ”

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Please would you comment on this ?

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http://www.postgresql.org/docs/8.3/interactive/ddl-basics.html adds the following:

“There is a limit on how many columns a table can contain. Depending on the column types, it is between 250 and 1600. However, defining a table with anywhere near this many columns is highly unusual and often a questionable design.”

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