Query goal: | Find base table columns that based on the name seem to hold truth values. Find columns that name starts with "is_" or "has_" or "can_" or "on_" and that do not have Boolean type. |
Notes about the query: | The query assumes that the names are using snake_case style. The query considers both column names in English and Estonian. |
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: | Specify for each column a right data type that takes into account expected values in the column. Use Boolean type instead of emulating it based on some other data type. Change the column type to BOOLEAN. |
Data source: | INFORMATION_SCHEMA+system catalog |
SQL query: | Click on query to copy it
WITH fk_columns AS (select target_schema as table_schema, target_table as table_name, a.attname as column_name from (select (select nspname from pg_namespace where oid=c.relnamespace) as target_schema, c.relname as target_table, c.oid as target_table_oid, unnest(o.conkey) AS target_col from pg_constraint o inner join pg_class c on c.oid = o.conrelid where o.contype = 'f') t inner join pg_attribute a on t.target_col = a.attnum and t.target_table_oid = a.attrelid and a.attisdropped = false) SELECT c.table_schema, c.table_name, c.column_name, c.data_type, c.character_maximum_length, coalesce(c.column_default, d.domain_default) AS column_default, c.is_nullable FROM INFORMATION_SCHEMA.columns AS c LEFT JOIN INFORMATION_SCHEMA.domains AS d USING (domain_schema, domain_name) WHERE column_name~*'^(is|has|can|on)_' AND (c.data_type<>'boolean') AND (table_schema, table_name) IN (SELECT table_schema, table_name FROM INFORMATION_SCHEMA.tables WHERE table_type='BASE TABLE') AND 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 NOT EXISTS (SELECT * FROM fk_columns WHERE fk_columns.table_schema=c.table_schema AND fk_columns.table_name=c.table_name AND fk_columns.column_name=c.column_name) ORDER BY c.table_schema, c.table_name, c.column_name; |
Collection name | Collection description |
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Find problems about base tables | A selection of queries that return information about the data types, field sizes, default values as well as general structure of base tables. Contains all the types of queries - problem detection, software measure, and general overview |
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 . |
Lexicon bad smells and linguistic antipatterns | Queries made to find the occurrences of lexicon bad smells and linguistic antipatterns |
Category name | Category description |
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Boolean data | Queries of this category provide information about truth-values data that is kept in the database. |
Data types | Queries of this category provide information about the data types and their usage. |
Naming | Queries of this category provide information about the style of naming. |
Result quality depends on names | Queries of this category use names (for instance, column names) to try to guess the meaning of a database object. Thus, the goodness of names determines the number of false positive and false negative results. |
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). |
Reference |
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Linguistic antipattern "D.2 Name suggests boolean but type is not": Arnaoudova, V., Di Penta, M., Antoniol, G., 2016. Linguistic antipatterns: What they are and how developers perceive them. Empirical Software Engineering, 21(1), pp.104-158. |
https://stackoverflow.com/questions/3037188/naming-of-boolean-column-in-database-table |