MySQL: Allow optional constraint name after CONSTRAINT keyword #2183
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MySQL allows `CONSTRAINT CHECK (expr)` without a name - the database will auto-generate a constraint name. This is a MySQL extension; the SQL standard requires a name after the CONSTRAINT keyword. See [docs]. Previously, we required an identifier after CONSTRAINT, causing us to interpret CONSTRAINT as a column name in cases like: ```sql CREATE TABLE t (x INT, CONSTRAINT CHECK (x > 1)) ``` Now we check if the token after CONSTRAINT is a constraint type keyword (CHECK, PRIMARY, UNIQUE, FOREIGN) and treat the name as optional for dialects that support this. This is just MySQL as far as I know (and Generic), but we introduce a new `Dialect` flag even though it's a minor feature. We could remove the flag and allow the more permissive optional name syntax across dialects if desired. [docs]: https://dev.mysql.com/doc/refman/8.4/en/create-table.html
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MySQL allows
CONSTRAINT CHECK (expr)without a name - the database will auto-generate a constraint name. This is a MySQL extension; the SQL standard requires a name after the CONSTRAINT keyword. See docs.Previously, we required an identifier after CONSTRAINT, causing us to interpret CONSTRAINT as a column name in cases like:
Now we check if the token after CONSTRAINT is a constraint type keyword (CHECK, PRIMARY, UNIQUE, FOREIGN) and treat the name as optional for dialects that support this. This is just MySQL as far as I know (and Generic), but we introduce a new
Dialectflag even though it's a minor feature. We could remove the flag and allow the more permissive optional name syntax across dialects if desired.