| 641 | Do not create multiple columns for the same attribute | Find base tables that implement recording multivalued attribute values with the help of repeating group of columns. Find base tables that have more than one columns with the same type and field size and the difference between the columns are the numbers in the column names (column1, column2, etc.). | Problem detection | INFORMATION_SCHEMA only | 2021-03-18 15:57 | MIT License | |
| 642 | Do not clone tables | Find cases where a base table has been split horizontally into multiple smaller base tables based on the distinct values in one of the columns of the original table. Each such newly created table has the name, a part of which is a data value from the original tables. Find base tables that have the same columns (column name, column order, data type) and the difference between the tables are the numbers in the table names (table1, table2, etc.). | Problem detection | INFORMATION_SCHEMA only | 2021-03-18 14:43 | MIT License | |
| 643 | Do not leave out the referential constraints (based on classifiers) | Find non-key and non-foreign columns of base tables with a textual column and small field size in case of which there is a table with the name that is similar to the column name. Perhaps the table is a classifier table and the column should have a foreign key constraint referencing to the table. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-18 11:14 | MIT License | |
| 644 | Do not leave out the referential constraints (based on adjacency list design) | Try to find missing foreign key constraints. Find non-key and non-foreign key columns of base tables that do not have an associated sequence generator, and that name refers to the possibility that the column holds parent identifiers. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-18 11:13 | MIT License | |
| 645 | All supertables | Find all the base tables that serve as supertables in the inheritance hierarchies | Sofware measure | system catalog base tables only | 2021-03-14 17:07 | MIT License | |
| 646 | Do not use FLOAT Data Type | Find base table columns that have FLOAT, REAL, or DOUBLE PRECISION type. "The data types real and double precision are inexact, variable-precision numeric types. On all currently supported platforms, these types are implementations of IEEE Standard 754 for Binary Floating-Point Arithmetic (single and double precision, respectively), to the extent that the underlying processor, operating system, and compiler support it." (PostgreSQL documentation) Do not use the approximate numeric types FLOAT, REAL, and DOUBLE PRECISION in order to present fractional numeric data. Due to the use of the IEEE 754 standard the results of calculations with the values, which have one of these types, can be inexact because out of necessity some numbers must be rounded to a value, which is very close. "Comparing two floating-point values for equality might not always work as expected." (PostgreSQL documentation) | Problem detection | INFORMATION_SCHEMA only | 2021-03-12 15:41 | MIT License | |
| 647 | Do not always depend on one's parent | Find where a hierarchical structure is implemented in a base table by adding a foreign key that refers to a candidate key of the same table. | General | system catalog base tables only | 2021-03-12 15:36 | MIT License | |
| 648 | Disabled system triggers (i.e., disabled enforcement of constraints) | These triggers should be enabled because otherwise some important functionality regarding constraints like enforcing referential integrity does not work. | Problem detection | system catalog base tables only | 2021-03-12 15:06 | MIT License | |
| 649 | Do not format comma-separated lists (based on user data) | Find, based on the data that users have recoreded in a database, cases where a multi-valued attribute in a conceptual data model is implemented as a textual column of a base table. Expected values in the column are strings that contain attribute values, separated by commas or other separation characters. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-12 15:02 | MIT License | |
| 650 | Different foreign key column names in case of referencing the same candidate key | Find the cases when the names of columns in different foreign keys that reference to the same candidate key are different. If different names reflect different roles, then it is legitimate. However, there could also be accidental differences that makes it more difficult to use the database. | Problem detection | system catalog base tables only | 2021-03-12 11:21 | MIT License | |
| 651 | Referential degree of tables | This metric represents the number of foreign keys in a base table. | Sofware measure | INFORMATION_SCHEMA only | 2021-03-12 11:07 | MIT License | |
| 652 | Referential degree of tables (ver 2) | Find how many base tables are referenced from a base table by using foreign keys. | Sofware measure | system catalog base tables only | 2021-03-12 11:06 | MIT License | |
| 653 | The number of referencing base tables | Find how many base tables reference to a base table by using foreign keys. The more references there are the more impact the change of the table could have to the overall system. | Sofware measure | system catalog base tables only | 2021-03-12 11:02 | MIT License | |
| 654 | Potentially a classifier is missing (based on field sizes) | Find columns that are not covered by a primary key, unique, and foreign key constraint but have a textual type with the maximum field size 3 or less. | General | INFORMATION_SCHEMA+system catalog base tables | 2021-03-10 13:07 | MIT License | |
| 655 | Do not assume you must use files (based on user data) | Find cases where you store images and other media as files outside the database and store in the database only paths to the files. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-10 12:58 | MIT License | |
| 656 | Do not format comma-separated lists (based on column names) | Find, based on column names, cases where a multi-valued attribute in a conceptual data model is implemented as a textual column of a base table or a foreign table. Expected values in the column are strings that contain attribute values, separated by commas or other separation characters. | Problem detection | INFORMATION_SCHEMA only | 2021-03-10 12:57 | MIT License | |
| 657 | Do not leave out the referential constraints (islands) | Try to find missing foreign key constraints. Find base tables that do not participate in any referential constraint (as the referenced table or as the referencing table). These tables are like "islands" in the database schema. | Problem detection | system catalog base tables only | 2021-03-10 12:20 | MIT License | |
| 658 | Inconsistency of using column data types/field sizes in case of columns that implement relationships | Find foreign key constraints where the candidate key columns (belong to a PRIMARY KEY/UNIQUE constraint) and foreign key columns do not have the same data type and field size. Primary key/unique columns and foreign key columns should have the same data type and field size. If, for instance, the primary key column has type INTEGER and foreign key column has type SMALLINT, then one cannot use all the primary key values as foreign key values. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-10 12:13 | MIT License | |
| 659 | Some candidate key values cannot be used as foreign key values | Find foreign key constraints in case of which some candidate key values cannot be used as foreign key values. Primary key/unique columns and foreign key columns should have the same data type and field size. If, for instance, the primary key column has type INTEGER and foreign key column has type SMALLINT, then one cannot use all the primary key values as foreign key values. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-10 12:13 | MIT License | |
| 660 | Foreign key references a non-key (has optional columns) | Find foreign key constraints that referenced column is optional. | Problem detection | INFORMATION_SCHEMA+system catalog base tables | 2021-03-10 12:12 | MIT License | |