PostgreSQL Query Catalog

This query identifies non-foreign key columns of base tables with a textual data type that lack any simple (single-column) CHECK constraint. The absence of such constraints indicates a complete lack of column-level validation, creating a risk of low-quality data ingress, including the implicit allowance of empty or whitespace-only strings.

Find base table columns with an array type. Think through as to whether a column with an array type could be replaced with a separate table.

This query generates a list of all base tables where the FILLFACTOR has been explicitly set to a value other than the default of 100. This non-default setting is a deliberate performance tuning decision, intended to reserve free space within table pages to improve the efficiency of UPDATE operations by facilitating HOT updates. The query provides a comprehensive list for administrators to audit these customizations and verify that they are still necessary and appropriate for the current table workload.

This query identifies base table columns whose names suggest they store national identification numbers (personal codes), specifically targeting those that serve as a primary or unique key. Using a national ID as a standalone key enforces a highly restrictive business rule: it assumes that all individuals in the system come from a single country, as identical ID numbers can exist in different countries. The query flags these instances to prompt a review, ensuring that this single-country limitation is intentional and actually aligns with the domain rules.

Identify possibly missing CHECK constraints.

Find base tables and materialized views that do not have any index.

A surrogate key is a primary key that consist of one column. The values of this column do not have any meaning for the user and the system usually generates the values (integers) automatically. In case of defining a surrogate key in a table it is a common mistake to forget declaring existing natural keys in the table. If a key covers an optional column then it does not prevent duplicate rows where some values are missing and other values are equal. Because NULL is not a value and is not duplicate of another NULL the, follwing is possible: CREATE TABLE Uniq(a INTEGER NOT NULL,
b INTEGER,
CONSTRAINT ak_uniq UNIQUE (a, b));

INSERT INTO Uniq(a, b) VALUES (1, NULL);
INSERT INTO Uniq(a, b) VALUES (1, NULL);

This query identifies tables that use a single-column surrogate primary key but lack any other UNIQUE constraints or unique indexes. The absence of additional unique constraints suggests that the natural business key has not been enforced, creating a risk of data duplication that violates business rules. Tables consisting of only a single column are excluded from this check.

Find base tables without any unique constraints and primary key as well as any unique index, whether it is created explicitly by a developer or automatically by the DBMS. The only legitimate reason of such a table is if it is an abstract table that is used to define common columns of subtables.

Find the base tables where all the unique columns are optional. In such tables there can be rows without values that identify these rows. In this case there can be rows in the table where the values that should identify the row are missing.

Find base tables where uniqueness is achieved by using only unique indexes, i.e., there is at least one unique index but no uniqueness constraints (PRIMARY KEY, UNIQUE, EXCLUDE)

Find base tables where statistics has not been collected at all or it has been lastly collected more than 40 days ago.

Find base table and foreign table columns with the Boolean type that has a CHECK constraint that involves only this column. Avoid unnecessary CHECK constraints. The Boolean type contains only two values and there is nothing to check. By creating a check that determines that possible values in the column are TRUE and FALSE, one duplicates the attribute constraint (column has a type). This is a form of duplication.

Find base table columns with the Boolean type that has a PRIMARY KEY, UNIQUE, or FOREIGN KEY constraint that involves only this column. Avoid unnecessary constraints. It is quite improbable that there must be such constraints. For instance, a table with PRIMARY KEY () or UNIQUE () constraint can have at most two rows.

Find base table columns that are covered by a primary key or a unique constraint and that probably have a static default value.

Find base table primary key and unique constraints where all columns probably have a static default value. Candidate key columns (columns that belong to the primary key or to an unique constraints) shouldn't have static default values unless you are enforcing a rule that a table can have at most one row. The point of default values is that system assigns them automatically. There cannot be multiple rows with the same key value.

Find CHECK constraints on base table or foreign table columns that contain data about e-mail addresses and apply unnecessary restrictions to the these, rejecting potentially some legal addresses. More precisely, find CHECK constraints that prevent registration of e-mail addresses with multiple @ signs.

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.

Refers to the column pg_proc.prokind and thus works starting from PostgreSQL 11. Find user-defined routines and derived tables (views/materialized views) that have a subquery with case insensitive search (by using the upper or lower function or ILIKE predicate or (?i) modifier of a regular expression pattern).

Find sets of columns that have both case sensitive and case insesitive unique constraints enforced based on these columns. In case of textual columns uniqueness could be checked either in case sensitive or case insensitive way. It is a contradiction to check the uniqueneness in both ways in case of the same key.