Query goal: | 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. |
Query type: | Problem detection (Each row in the result could represent a flaw in the design) |
Query reliability: | Low (Many false-positive results) |
Query license: | MIT License |
Fixing suggestion: | Declare the NOT NULL constraint if it is missing. If the column is associated with a domain, then decide as to wheter to associate the NOT NULL constraint with the domain instead of declaring it directly to the column. |
Data source: | INFORMATION_SCHEMA+system catalog |
SQL query: | Click on query to copy it
WITH unique_columns AS (SELECT n.nspname AS table_schema, c2.relname AS table_name, a.attname AS column_name FROM pg_catalog.pg_class AS c INNER JOIN pg_catalog.pg_index AS i ON i.indexrelid = c.oid INNER JOIN pg_catalog.pg_class AS c2 ON i.indrelid = c2.oid INNER JOIN pg_catalog.pg_namespace AS n ON c.relnamespace = n.oid INNER JOIN pg_catalog.pg_authid AS u ON n.nspowner = u.oid INNER JOIN pg_catalog.pg_attribute AS a ON a.attrelid = c.oid WHERE c.relkind = 'i' AND i.indisunique=TRUE AND a.attnum>=1 AND a.attisdropped = FALSE AND (n.nspname = 'public' OR u.rolname <> 'postgres')) SELECT A.table_schema, A.table_name , A.column_name, CASE WHEN A.data_type ILIKE 'character%' AND A.character_maximum_length IS NOT NULL THEN A.data_type || '(' || A.character_maximum_length::text || ')' WHEN A.data_type ILIKE 'timestamp%' AND A.datetime_precision IS NOT NULL THEN A.data_type || '(' || A.datetime_precision || ')' WHEN A.data_type ILIKE 'numeric%' AND A.numeric_precision IS NOT NULL THEN A.data_type || '(' || A.numeric_precision::text || ',' ||coalesce(A.numeric_scale,0)::text || ')' WHEN A.data_type ILIKE 'interval%' AND A.interval_type IS NOT NULL THEN A.data_type || '(' || A.interval_type::text || ')' WHEN A.data_type='USER-DEFINED' THEN A.udt_schema || '.' || A.udt_name ELSE A.data_type END AS data_type 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 is_nullable='YES' AND T.table_type='BASE TABLE' AND (A.table_schema = 'public' OR S.schema_owner<>'postgres') AND (table_schema, table_name, column_name) IN (SELECT table_schema, table_name, column_name FROM unique_columns) ORDER BY table_schema, table_name, ordinal_position; |
SQL query | Description |
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WITH unique_columns AS (SELECT n.nspname AS table_schema, c2.relname AS table_name, a.attname AS column_name FROM pg_catalog.pg_class AS c INNER JOIN pg_catalog.pg_index AS i ON i.indexrelid = c.oid INNER JOIN pg_catalog.pg_class AS c2 ON i.indrelid = c2.oid INNER JOIN pg_catalog.pg_namespace AS n ON c.relnamespace = n.oid INNER JOIN pg_catalog.pg_authid AS u ON n.nspowner = u.oid INNER JOIN pg_catalog.pg_attribute AS a ON a.attrelid = c.oid WHERE c.relkind = 'i' AND i.indisunique=TRUE AND a.attnum>=1 AND a.attisdropped = FALSE AND (n.nspname = 'public' OR u.rolname <> 'postgres')) 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 USING (table_schema, table_name) INNER JOIN information_schema.schemata S ON A.table_schema=S.schema_name WHERE is_nullable='YES' AND T.table_type='BASE TABLE' AND (A.table_schema = 'public' OR S.schema_owner<>'postgres') AND (table_schema, table_name, column_name) IN (SELECT table_schema, table_name, column_name FROM unique_columns) ORDER BY table_schema, table_name, ordinal_position; | Declare NOT NULL constraint to the column. |
Collection name | Collection description |
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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 . |
Category name | Category description |
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Missing data | Queries of this category provide information about missing data (NULLs) in a database. |
Uniqueness | Queries of this category provide information about uniqueness constraints (PRIMARY KEY, UNIQUE, EXCLUDE) as well as unique indexes. |
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). |