44 lines
2.5 KiB
PL/PgSQL
44 lines
2.5 KiB
PL/PgSQL
create function immutable(schema text, table_ text, columns text[])
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returns void
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language plpgsql
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as $$
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declare
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col text;
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qualified_name text := concat(schema, '.', table_);
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do_table_immutable_columns text := concat('do_', table_, '_immutable_columns');
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trigger_table_immutable_columns text := concat('trigger_', table_, '_immutable_columns');
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create_do_table_immutable_columns text;
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create_trigger_table_immutable_columns text;
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begin
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create_do_table_immutable_columns := concat( create_do_table_immutable_columns
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, 'create function ', schema, '.', do_table_immutable_columns, E'() returns trigger language plpgsql as \$\$\n'
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, E'begin\n'
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, ' if OLD.', columns[1], ' <> NEW.', columns[1], E' then\n'
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, E' raise exception \'', qualified_name, '.', columns[1], E' is immutable\' using errcode = \'restrict_violation\';\n'
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);
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foreach col in array columns[2:] loop
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create_do_table_immutable_columns := concat( create_do_table_immutable_columns
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, E' elsif OLD.', col, ' <> NEW.', col, E' then\n'
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, E' raise exception \'', qualified_name, '.', col, E' is immutable\' using errcode = \'restrict_violation\';\n'
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);
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end loop;
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create_do_table_immutable_columns := concat( create_do_table_immutable_columns
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, E' end if;\n'
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, E'\n'
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, E' return NEW;\n'
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, E'end;\n'
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, E'\$\$;\n'
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);
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create_trigger_table_immutable_columns := concat( create_trigger_table_immutable_columns
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, 'create trigger ', trigger_table_immutable_columns, E'\n'
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, 'before update on ', qualified_name, E'\n'
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, 'for each row execute function ', do_table_immutable_columns, '();'
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);
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execute create_do_table_immutable_columns;
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execute create_trigger_table_immutable_columns;
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end;
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$$;
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