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In the trigger body, how can I get a value of NEW by the field name?

This is what I want to do:

some_key = "some_column";

value := NEW[some_key];
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  • This is not possible. May be you could explain the problem you're trying to solve, instead of your impossible solution to that problem. Commented Nov 16, 2019 at 14:12

1 Answer 1

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You have to use dynamic SQL like this:

EXECUTE format('SELECT $1.%I', some_key) INTO value USING NEW;
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  • Your solution is correct, thank you very much. I managed to solve the problem. See part of the code. code FOR ri IN SELECT ordinal_position, column_name, data_type FROM information_schema.columns WHERE table_schema = quote_ident(TG_TABLE_SCHEMA) AND table_name = quote_ident(TG_TABLE_NAME) AND column_name = quote_ident(nmpk) ORDER BY ordinal_position LOOP EXECUTE 'SELECT ($1).' || ri.column_name || '::text' INTO t USING NEW; idValue := t; END LOOP; Commented Nov 19, 2019 at 10:22
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    If the answer is correct, you might accept it. Concatenating column names with || is a bad idea because of the risk of SQL injection. Use the format function like I did in my answer. Commented Nov 19, 2019 at 10:30

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