Re: "RETURNING PRIMARY KEY" syntax extension

Ian Barwick wrote
> Hi,
> 
> The JDBC API provides the getGeneratedKeys() method as a way of retrieving
> primary key values without the need to explicitly specify the primary key
> column(s). This is a widely-used feature, however the implementation has
> significant
> performance drawbacks.
> 
> Currently this feature is implemented in the JDBC driver by appending
> "RETURNING *" to the supplied statement. However this means all columns of
> affected rows will be returned to the client, which causes significant
> performance problems, particularly on wide tables. To mitigate this, it
> would
> be desirable to enable the JDBC driver to request only the primary key
> value(s).

Seems like a good idea.


>      ERROR:  Relation does not have any primary key(s)

"Relation does not have a primary key."
or
"Relation has no primary key." (preferred)

By definition it cannot have more than one so it must have none.

It could have multiple unique constraints but I do not believe they are
considered if not tagged as primary.

David J.





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