Goal Find base table columns that have Boolean type and do not have NOT NULL constraint. Use two-valued logic (TRUE, FALSE) instead of three-valued logic (TRUE, FALSE, UNKNOWN). Because NULL in a Boolean column means unknown make all the Boolean columns mandatory.
Notes The query finds all base table columns that have the type Boolean and that are optional.
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)
Fixing Suggestion Make the column mandatory by declaring NOT NULL constraint to it.
Data Source INFORMATION_SCHEMA only
SQL Query 
SELECT A.table_schema, A.table_name , A.column_name
FROM information_schema.columns A INNER JOIN information_schema.tables T USING (table_schema, table_name)
INNER JOIN information_schema.schemata S ON A.table_schema=S.schema_name
WHERE A.data_type='boolean' 
AND is_nullable='YES' 
AND T.table_type='BASE TABLE'
AND (A.table_schema = 'public'
OR S.schema_owner<>'postgres')
ORDER BY A.table_schema, A.table_name, A.column_name;

SQL statements that help generate fixes for the identified problem.

Fix Action #1
SELECT format('ALTER TABLE %1$I.%2$I ALTER COLUMN %3$I SET NOT NULL', A.table_schema, A.table_name , A.column_name) AS statements
FROM information_schema.columns A
INNER JOIN information_schema.tables T
ON A.table_schema = T.table_schema
AND A.table_name = T.table_name
INNER JOIN information_schema.schemata S
ON A.table_schema=S.schema_name
WHERE A.data_type='boolean' AND is_nullable='YES' AND T.table_type='BASE TABLE'
AND (A.table_schema = 'public'
OR S.schema_owner<>'postgres')
ORDER BY A.table_schema, A.table_name, A.column_name;

Apply the NOT NUL L constraint directly to the column.

SQL Query to Generate FixDescription
SELECT format('ALTER TABLE %1$I.%2$I ALTER COLUMN %3$I SET NOT NULL', A.table_schema, A.table_name , A.column_name) AS statements
FROM information_schema.columns A
INNER JOIN information_schema.tables T
ON A.table_schema = T.table_schema
AND A.table_name = T.table_name
INNER JOIN information_schema.schemata S
ON A.table_schema=S.schema_name
WHERE A.data_type='boolean' AND is_nullable='YES' AND T.table_type='BASE TABLE'
AND (A.table_schema = 'public'
OR S.schema_owner<>'postgres')
ORDER BY A.table_schema, A.table_name, A.column_name;
Apply the NOT NUL L constraint directly to the column.

Collections

This query belongs to the following collections:

Find problems about integrity constraints

A selection of queries that return information about the state of integrity constraints in the datadabase. Contains all the types of queries - problem detection, software measure, and general overview

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 .

NameDescription
Find problems about integrity constraintsA selection of queries that return information about the state of integrity constraints in the datadabase. Contains all the types of queries - problem detection, software measure, and general overview
Find problems automaticallyQueries, 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:

Boolean data

Queries of this category provide information about truth-values data that is kept in the database.

Comfortability of data management

Queries of this category provide information about the means that have been used to make the use or management of database more comfortable and thus, more efficient.

Missing data

Queries of this category provide information about missing data (NULLs) in a database.

NameDescription
Boolean dataQueries of this category provide information about truth-values data that is kept in the database.
Comfortability of data managementQueries of this category provide information about the means that have been used to make the use or management of database more comfortable and thus, more efficient.
Missing dataQueries of this category provide information about missing data (NULLs) in a database.