Find the number of mandatory and optional Boolean base table columns and the proportion of optional columns from all the Boolean columns. 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.
Type
Sofware measure (Numeric values (software measures) about the database)
SELECT Count(*) AS nr_of_Boolean_cols,
Count(*) FILTER (WHERE is_nullable='NO') AS nr_of_mandatory_Boolean_cols,
Count(*) FILTER (WHERE is_nullable='YES') AS nr_of_optional_Boolean_cols,
CASE WHEN Count(*)=0 THEN NULL ELSE Round((Count(*) FILTER (WHERE is_nullable='YES')*100)/ Count(*),1) END AS percentage_of_optional_Boolean_cols
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 T.table_type='BASE TABLE'
AND (A.table_schema = 'public'
OR S.schema_owner<>'postgres');
Collections
This query belongs to the following collections:
Name
Description
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 by overview
Queries that results point to different aspects of database that might have problems. A human reviewer has to decide based on the results as to whether there are problems or not .
Categories
This query is classified under the following categories:
Name
Description
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.