[HACKERS] Undefined psql variables
| От | Corey Huinker |
|---|---|
| Тема | [HACKERS] Undefined psql variables |
| Дата | |
| Msg-id | CADkLM=eFUs3VHT9tZp_5WEAZoywpV_YF=44KUwKRVf-z=hmsoA@mail.gmail.com обсуждение исходный текст |
| Ответы |
Re: [HACKERS] Undefined psql variables
Re: [HACKERS] Undefined psql variables |
| Список | pgsql-hackers |
I was giving some thought to how psql handles undefined variables.
I would like an option where either psql can provide an alternate value when an undefined variable is referenced, or a way to detect that a specific variable is undefined and replace it with a defined variable.
My first thought thought was to have a
\set_if_undefined var_name 'default_value'
Another idea adding a \pset parameter that would return a specific value when an undefined psql variable is referenced instead of raising an error. Like this:
# select :'x' as value_of_x;ERROR: syntax error at or near ":"LINE 1: select :'x' as value_of_x;^# \pset variable_default ''analytics=# select :'x' as value_of_x;value_of_x------------(1 row)# \pset variable_default ''# select :'x' as value_of_x;ERROR: syntax error at or near ":"LINE 1: select :'x' as value_of_x;^
This would end up having behavior somewhat similar to +e/-e in bash, where a paranoid script could do something like this:
\pset variable_default 'default1'select :'required_var1' as required_var1 \gset\pset variable_default 'default2'select :'required_var2' as required_var2 \gset-- reset to default behavior\pset variable_default error
Thus setting sane defaults to vars that weren't assigned at invocation time.
Thoughts?
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