PostgreSQL Query Catalog

Find statistics about how many base tables have how many derived tables that use these tables.

Find the number of views, the number of views with and without security barrier setting, and the names of views with and without the security barrier setting.

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.

Find one-to-one relationships between base tables. In this case the foreign key columns must have primary key or unique constraint. These tables could implement inheritance hierarchy that has been specified in the conceptual data model.

Find base base tables have the simple primary key that contains a column with the (case insensitive) name id and an integer type. In addition, the primary key values are generated automatically by the system by using a sequence generator. In addition the base table must not have any unique constraint.

Find columns of base tables or foreign tables in case of which a check constraint on the column permits only one value in the column. The constraint may be correct if it is applied to a column of a subtable that is inherited from the supertable or is used to enfore the rule that the table can have at most one row.

Find columns of base tables or foreign tables in case of which the type of the column permits only one value in the column. The type is an enumeration type that specifies only one value.

Find columns of base tables or foreign tables in case of which a check constraint on the column permits only one value in the column. Exclude columns that are inherited from a supertable because the constraint may be correct if it is applied to a column of a subtable that is inherited from the supertable.

Find optional base table columns, i.e., columns that permit NULLs. Are you sure you want to allow NULLs in these columns?

Find optional base table columns that participate in a UNIQUE constraint or index. Each base table has one or more candidate keys. One of these is usually selected to be the primary key, other are called alternate keys. To enforce an alternate key one should define a UNIQUE constraint and determine that all the key columns are mandatory (NOT NULL) just like the primary key columns are mandatory. Make sure that the NOT NULL constraint is not missing on these columns.

Find cases where optional columns are before a mandatory column. Place mandatory columns before optional columns to improve comprehensibility of the table.

Find optional composite foreign keys that do not have MATCH FULL specified. Without MATCH FULL the system will permit partial foreign key values

Find foreign key columns that do not have the NOT NULL constraint. It is better to limit the use of NULLs and optional columns due to the problems that it causes in interpreting the query results, making queries, and enforcing constraints. In addition, one should check as to whether this kind of design is consistent with the multiplicities in the conceptual data model.

Find optional base table columns that participate in a UNIQUE constraint or index but do not participate in a foreign key constraint. Each base table has one or more candidate keys. One of these is usually selected to be the primary key, other are called alternate keys. To enforce an alternate key one should define a UNIQUE constraint and determine that all the key columns are mandatory (NOT NULL) just like the primary key columns are mandatory. Make sure that the NOT NULL constraint is not missing on these columns.

Find non-function based indexes (both unique and non-unique) that have identical first column but the operator class that is used in case of the first column is different. Include unique indexes that support a constraint (primary key, unique, exclude), i.e., these indexes have been automatically created due to the constraint declaration.

Find non-function based indexes (both unique and non-unique) that duplicate each other because their first column is identical and the operator class that is used in case of the first column is identical. Include unique indexes that support a constraint (primary key, unique, exclude), i.e., these indexes have been automatically created due to the constraint declaration.

Make sure that there is genuine overloading instead of duplication or dead code. "In some programming languages, function overloading or method overloading is the ability to create multiple functions of the same name with different implementations." (Wikipedia) In PostgreSQL one can do it automagically by having multiple routines with the same name but different parameters in the same schema.

Routines in the same schema that have the same name and that have parameters with different types or different number of parameters are not considered to be in conflict at the creation time. However, if defaults are provided in the definition of parameters, then these routines might be conflict during runtime.

What are the pairs of base tables that have at least two columns with the same names and data types. The tables might violate the principle of orthogonal design and hence might facilitate uncontrolled data redundancy over different tables.

Find non-key base table columns with the same name and type that have different default values. Be consistent. Columns with the same name and type shouldn't probably have different default values in case of different tables. "If you do something a certain way, do all similar things in the same way." (Robert C. Martin, Clean Code)