| Seq nr | Name▲ | Goal | Type | Data source | Last update | License | ... |
|---|---|---|---|---|---|---|---|
| 1 | All foreign key constraints | Enforce referential integrity in database. Find all referential integrity (foreign key) constraints. | General | system catalog base tables only | 2023-12-07 12:48 | MIT License | |
| 2 | Cascading update is not needed (based on surrogate keys) | Find foreign key constraints that reference to a candidate key that is a surrogate key, i.e., its values are generated by the system by using sequence generators. Do not use ON UPDATE CASCADE, ON UPDATE SET NULL, and ON UPDATE SET DEFAULT in case of foreign keys that reference to surrogate keys. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2024-11-28 12:31 | MIT License | |
| 3 | Chains of ON DELETE CASCADE | Find all referential paths (chains of of parent-child tables that are associated through foreign key constraints) where all foreign key constraints have ON DELETE CASCADE compensating actions. Be careful with too long chains. | General | system catalog base tables only | 2022-10-29 20:04 | MIT License | |
| 4 | Foreign keys with ON DELETE CASCADE | Find referential constraints (foreign key constraints) that employ ON DELETE CASCADE compensatory action. ON DELETE CASCADE should only be used if it has been created based on a generalization or a composition in the conceptual data model or if the foreign key connects a table that corresponds to the main entity type with a table that corresponds to a non-main entity type. | General | system catalog base tables only | 2020-11-16 10:15 | MIT License | |
| 5 | Foreign keys with ON UPDATE CASCADE | Referential constraints (foreign key constraints) that employ ON UPDATE CASCADE compensatory action. ON UPDATE CASCADE should only be used if the referenced key is a natural key (its values can be changed). | General | system catalog base tables only | 2020-11-15 15:39 | MIT License | |
| 6 | Inconsistent chain of relationships in terms of using ON UPDATE compensating action | In case of a chain of relationships between tables (where the primary key and the foreign key have the same columns) the use of ON UPDATE compensating action should be consistent. For instance, in the next example there is inconsistency, because if one changes the person_code in table Person, then the modification does not succeed because it does not cascade to the table Product. It is unclear as to whether it should be possible to change the person_code or not. Person (person_code, surname) Primary key (person_code) Worker(person_code) Primary key (person_code) Foreign key (person_code) References Person (person_code) ON UPDATE CASCADE Product(product_code, registrator) Primary key (product_code) Foreign key (registrator) References Worker (person_code) ON UPDATE NO ACTION | Problem detection | system catalog base tables only | 2024-11-28 12:43 | MIT License | |
| 7 | ON DELETE CASCADE is not needed (based on classifier tables) | Find foreign key constraints with ON DELETE CASCADE compensating action that refer to classifier (reference data) tables. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2023-12-08 14:52 | MIT License | |
| 8 | ON DELETE CASCADE is probably missing (based on the multiplicity of the relationship) | Find foreign key constraints that completely overlap with a candidate key constraint (primary key or unique constraint) but the foreign key constraint does not have the ON DELETE CASCADE compensating action. In this case there is a foreign key that implements a relationship type between a strong entity type and a weak entity type (1-1 relationship type). Therefore, in this case ON DELETE CASCADE is an appropriate compensating action. | Problem detection | system catalog base tables only | 2021-02-25 17:29 | MIT License | |
| 9 | ON DELETE CASCADE is probably not needed (based on the relationship type) | Find foreign key constraints that implement a non-identifying relationship type and have ON DELETE CASCADE compensating action. If the identity of the parent table is not a part of the identity of the child table, then there is a non-identifying relationship type and most probably the foreign key should not have ON DELETE CASCADE. | Problem detection | system catalog base tables only | 2023-10-28 18:38 | MIT License | |
| 10 | ON DELETE SET NULL is probably missing | Find implementations of the adjacency list design pattern, where the corresponding foreign key columns are optional but the foreign key constraint does not have ON DELETE SET NULL compensating action. Implement adjacency list correctly. | Problem detection | system catalog base tables only | 2021-02-25 17:29 | MIT License | |
| 11 | ON UPDATE CASCADE is perhaps missing (based on the compensating actions of other foreign key constraints) | Find inconsistencies of using ON UPDATE CASCADE in case of foreign key constraints. An example of inconsistency is that there are two foreign key constraints in different tables that refer to the same table and its candidate key. One of the constraints has ON UPDATE CASCADE compensating action one does not. ON UPDATE CASCADE usage should be consistent, otherwise it does not allow us to change key values in the primary table. More generally, there is a set of foreign key constraints F that refer to a candidate key of table T. It cannot be the case that a proper non-empty subset of these foreign keys have ON UPDATE CASCADE compensatory action. Either all the constraints in F should have it or none of it should have it (depending on circumstances). | Problem detection | system catalog base tables only | 2022-04-30 18:39 | MIT License | |
| 12 | ON UPDATE CASCADE is probably missing (based on column names) | Find foreign key constraints that do not feature ON UPDATE CASCADE compensating action although people have a reason to change the key value in the primary table by assuming that the names of foreign key columns correctly point towards the use of natural keys in the table. | Problem detection | system catalog base tables only | 2023-11-16 11:59 | MIT License | |
| 13 | ON UPDATE CASCADE is probably missing (based on data types) | Find foreign key constraints where the foreign key column does not have an integer type or uuid type and the foreign key constraint does not have ON UPDATE CASCADE compensating action. In this case the foreign key probably refferes to a natural key (i.e., a key that values have meaning outside the computer system) and ON UPDATE CASCADE would be suitable because the key values could be changed over time. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2023-10-06 14:19 | MIT License | |
| 14 | ON UPDATE CASCADE is probably missing (based on the properties of the referenced column) | Find the foreign key constraints that do not have ON UPDATE CASCADE and that referenced key is a simple key that has an integer type, is not covered by another foreign key, and does not have an associated sequence generator, i.e., the foreign key references a simple natural key. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2022-04-30 18:39 | MIT License | |
| 15 | SET DEFAULT compensatory action is unsuitable | Find foreign keys with SET DEFAULT compensatory action where the foreign key column does not have a default value. Compensatory actions cannot make changes that violate integrity constraints in a database. SET DEFAULT means that there shoud be a default value at the foreign key column. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-02-25 17:30 | MIT License | |
| 16 | SET NULL compensatory action is unsuitable | Find foreign key constraints that use a SET NULL compensating action but a foreign key column is mandatory, i.e., does not permit NULLs. Compensatory actions cannot make changes that violate integrity constraints in a database. SET NULL cannot put NULL to a mandatory column (delete a foreign key value). | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-02-25 17:30 | MIT License | |
| 17 | The number of compensating actions of foreign key constraints | Find the number of compensating actions that are specified in case of foreign key constraints. | Sofware measure | system catalog base tables only | 2020-11-16 10:11 | MIT License |