After RENAME(ing) a Table I'm forced to use quoted identifiers

问题

After renaming a table in Postgres I'm experiencing a strange behaviour: if I reference the table without the quotes it doesn't work.

For example: the original name was «devices», after I've altered it to «Devices» the following SELECT breaks:

SELECT * from Devices

but this one

SELECT * from "Devices"

works as expected.

Any idea?

回答1:

Per the manual, identifiers are lower-cased unless quoted.

When you renamed it you did a RENAME TO "Devices", thus making the name mixed-case. You must now refer to it in quoted mixed case everywhere.

To PostgreSQL all these are names for the devices table:

• devices
• DEVICES
• Devices
• DeViCES

but these are names for separate tables with mixed-case names:

• "Devices"
• "DEVICES"

This is according to the SQL standard except that SQL requires implementations to UPPER CASE un-quoted names, where PostgreSQL for historical reasons lower cases them instead.

回答2:

Rename it again to devices (lower case without double quotes). Then you it will be possible to refer to it in any case you want including mixed case:

select * from dEvIceS

来源：https://stackoverflow.com/questions/17746491/after-renameing-a-table-im-forced-to-use-quoted-identifiers