so 16. 11. 2024 v 15:56 odesÃlatel Wolfgang Walther <walt...@technowledgy.de> napsal:
> Dmitry Dolgov: > > This sounds to me like an argument against allowing name clashing between > > variables and tables. It makes even more sense, since session variables > are in > > many ways similar to tables. > > +1 > It doesn't help too much, because the unique tuple (schema, name), and there is a search path. Secondly, the pg_class is not good enough for description of scalar variables, and enhancing pg_class for scalar variables can be messy. > > My mental model of a session variable is similar to a single-row, > optionally global temporary, table. > > Is there any substantial difference that I am not aware of? > What I know, the variables are used as query parameters, not as relations - Oracle, DB2, MSSQL, MySQL, ... semantically, yes - it is a global temporary object, but it can be scalar or composite value - it is not row. (global (temp)) table can hold 0, 1 or more rows (and rows are always composite of 0..n fields). The variable holds a value of some type. Proposed session variables are like plpgsql variables (only with different scope). In Postgres there is a difference between a scalar variable and composite variable with one field. Regards Pavel > Best, > > Wolfgang >
