Query goal: | SELECT statement should list the columns not use SELECT * to return data from all the columns. Firstly, it ensures, that the query asks only data that is really needed by the routine. It means less data that the DBMS has to fetch and pass to the routine. It could also mean that the DBMS can answer to a query based on an index without reading table blocks. Secondly, it documents the data that is returned by the query. The query does not consider objects that are a part of an extension. |
Notes about the query: | Refers to the column pg_proc.prokind and thus works starting from PostgreSQL 11. In the returned body of routine the query replaces each newline character with the line break (br) tag for the better readability in case the query result is displayed in a web browser. There could be multiple routines with the same name but with different parameters in the same schema (overloading). Thus, for the unique identification of the routine it is necessary to present also its parameters in addition to the schema name and routine name. The query excludes EXISTS predikate, i.e., "EXISTS ( SELECT *" is permitted. |
Query type: | Problem detection (Each row in the result could represent a flaw in the design) |
Query reliability: | High (Few or no false-positive results) |
Query license: | MIT License |
Data source: | INFORMATION_SCHEMA+system catalog |
SQL query: | Click on query to copy it
SELECT pg_namespace.nspname AS routine_schema, pg_proc.proname AS routine_name, pg_get_function_identity_arguments(pg_proc.oid) AS parameters, CASE WHEN pg_proc.prokind='f' THEN 'FUNCTION' WHEN pg_proc.prokind='p' THEN 'PROCEDURE' WHEN pg_proc.prokind='w' THEN 'WINDOW FUNCTION' END AS routine_type, regexp_replace(regexp_replace(pg_get_functiondef(pg_proc.oid),'[*]','<br><b>*</b>','g'),'[\r\n]','<br>','g') AS routine_src FROM pg_catalog.pg_proc, pg_catalog.pg_namespace WHERE pg_proc.pronamespace = pg_namespace.oid AND pg_proc.prokind<>'a' AND pg_get_functiondef(pg_proc.oid) ~*'(?<!EXISTS[[:space:]]*[(][[:space:]]*)SELECT[[:space:]]*\*' AND pg_namespace.nspname NOT IN (SELECT schema_name FROM INFORMATION_SCHEMA.schemata WHERE schema_name<>'public' AND schema_owner='postgres' AND schema_name IS NOT NULL) AND NOT EXISTS (SELECT 1 FROM pg_catalog.pg_depend d WHERE EXISTS (SELECT 1 FROM pg_catalog.pg_extension e WHERE d.refobjid=e.oid) AND d.objid=pg_proc.oid) ORDER BY routine_schema, routine_name, parameters; |
Collection name | Collection description |
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Find problems automatically | Queries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not . |
Category name | Category description |
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Comfortability of database evolution | Queries of this category provide information about the means that influence database evolution. |
Does not work in some earlier PostgreSQL version | Queries of this category provide information that was not available in some earlier PostgreSQL version |
Performance | Queries of this category provide information about indexes in a database. |
User-defined routines | Queries of this category provide information about the user-defined routines |
Reference |
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The corresponding code smell in case of cleaning code is "G26: Be Precise". (Robert C. Martin, Clean Code) |
https://stackoverflow.com/questions/3639861/why-is-select-considered-harmful |
https://stackoverflow.com/questions/321299/what-is-the-reason-not-to-use-select/321302 |
Rules 1 and 3 in: Delplanque, J., Etien, A., Auverlot, O., Mens, T., Anquetil, N., Ducasse, S.: CodeCritics applied to database schema: Challenges and first results. In: 2017 IEEE 24th International Conference on Software Analysis, Evolution and Reengineering (SANER), pp. 432-436. IEEE, (2017). |