Query goal: | Find check constraints that involve one column and are associated directly with a table where the Boolean expression invokes an operation that does not match with the data type of the column. |
Notes about the query: | The query considers only check constraints that are associated with one column. |
Query type: | Problem detection (Each row in the result could represent a flaw in the design) |
Query reliability: | Medium (Medium number of false-positive results) |
Query license: | MIT License |
Fixing suggestion: | Perhaps the Boolean expression is incorrect. For instance, CHECK(price::text<>''). In this case drop the constraint and think through what you have to check, whether the check is implemented already with the selection of the data type, and if not then what would be a correct Boolean expression. It could also be that the data type of the column is incorrect and has to be changed. |
Data source: | INFORMATION_SCHEMA+system catalog |
SQL query: | Click on query to copy it
WITH simple_checks AS (SELECT (select nspname from pg_namespace where oid=c.relnamespace) as table_schema, c.relname AS table_name, o.conname AS constraint_name FROM pg_constraint o INNER JOIN pg_class c ON c.oid = o.conrelid WHERE o.contype = 'c' AND cardinality(o.conkey)=1), checks AS (SELECT ccu.table_schema, ccu.table_name, c.column_name, c.ordinal_position, c.data_type, cc.constraint_name, cc.check_clause FROM INFORMATION_SCHEMA.constraint_column_usage AS ccu INNER JOIN INFORMATION_SCHEMA.check_constraints AS cc USING (constraint_schema, constraint_name) INNER JOIN INFORMATION_SCHEMA.columns AS c USING (table_schema, table_name, column_name) WHERE cc.check_clause NOT LIKE '%IS NOT NULL' AND ccu.table_schema NOT IN (SELECT schema_name FROM INFORMATION_SCHEMA.schemata WHERE schema_name<>'public' AND schema_owner='postgres' AND schema_name IS NOT NULL) AND (ccu.table_schema, ccu.table_name, cc.constraint_name) IN (SELECT table_schema, table_name, constraint_name FROM simple_checks)) SELECT table_schema, table_name, column_name, data_type, constraint_name, check_clause FROM checks WHERE (data_type !~* '^(character|text)' AND check_clause ~*'::(bpchar|character|text).*(=|>|<|~).*::(bpchar|character|text)' AND check_clause !~*'(to_date|to_timestamp)[(][^)]*::(bpchar|character|text)') OR (data_type ~* '^(character|text)' AND check_clause !~*'::(bpchar|character|text)' AND check_clause ~*'::') ORDER BY table_schema, table_name, ordinal_position; |
SQL query | Description |
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WITH simple_checks AS (SELECT (select nspname from pg_namespace where oid=c.relnamespace) as table_schema, c.relname AS table_name, o.conname AS constraint_name FROM pg_constraint o INNER JOIN pg_class c ON c.oid = o.conrelid WHERE o.contype = 'c' AND cardinality(o.conkey)=1), checks AS (SELECT ccu.table_schema, ccu.table_name, c.data_type, cc.constraint_name, cc.check_clause FROM INFORMATION_SCHEMA.constraint_column_usage AS ccu INNER JOIN INFORMATION_SCHEMA.check_constraints AS cc USING (constraint_schema, constraint_name) INNER JOIN INFORMATION_SCHEMA.columns AS c USING (table_schema, table_name, column_name) WHERE cc.check_clause NOT LIKE '%IS NOT NULL' AND ccu.table_schema NOT IN (SELECT schema_name FROM INFORMATION_SCHEMA.schemata WHERE schema_name<>'public' AND schema_owner='postgres' AND schema_name IS NOT NULL) AND (ccu.table_schema, ccu.table_name, cc.constraint_name) IN (SELECT table_schema, table_name, constraint_name FROM simple_checks)) SELECT format('ALTER TABLE %1$I.%2$I DROP CONSTRAINT %3$I;', table_schema, table_name, constraint_name) AS statements FROM checks WHERE (data_type !~* '^(character|text)' AND check_clause ~*'::(bpchar|character|text).*(=|>|<|~).*::(bpchar|character|text)' AND check_clause !~*'(to_date|to_timestamp)[(][^)]*::(bpchar|character|text)') OR (data_type ~* '^(character|text)' AND check_clause !~*'::(bpchar|character|text)' AND check_clause ~*'::') ORDER BY table_schema, table_name, constraint_name; | Drop the constraint. |
Collection name | Collection description |
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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 . |
Category name | Category description |
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CHECK constraints | Queries of this category provide information about CHECK constraints. |
Data types | Queries of this category provide information about the data types and their usage. |
Validity and completeness | Queries of this category provide information about whether database design represents the world (domain) correctly (validity) and whether database design captures all the information about the world (domain) that is correct and relevant (completeness). |