| 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 | 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. |
| Type | Problem detection (Each row in the result could represent a flaw in the design) |
| Reliability | High (Few or no false-positive results) |
| License | MIT (opens in new tab) |
| Data Source | INFORMATION_SCHEMA+system catalog |
| SQL Query |
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Collections
This query belongs to the following collections:
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 .
| Name | Description |
|---|---|
| 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 . |
Categories
This query is classified under the following categories:
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
| Name | Description |
|---|---|
| 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 |
Further reading and related materials:
The corresponding code smell in case of cleaning code is "G26: Be Precise". (Robert C. Martin, Clean Code)
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).
| Reference |
|---|
| 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). |