| Query goal: | The choice of data types should reveal as much as possible about the nature of the data in the column. The type of these columns could be CHAR(1) and they should have a constraint that a value in the column cannot be an empty string. |
| Notes about the query: | Query returns also information about columns that properties have been specified through a domain. |
| 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: | Change the type of the column and add the constraint. |
| Data source: | INFORMATION_SCHEMA only |
| SQL query: | Click on query to copy it
SELECT table_schema, table_name, column_name FROM INFORMATION_SCHEMA.columns WHERE (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 data_type = 'character varying' AND character_maximum_length=1 ORDER BY table_schema, table_name, ordinal_position; |
| Collection name | Collection description |
|---|---|
| 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 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 |
|---|---|
| Data types | Queries of this category provide information about the data types and their usage. |
| Reference |
|---|
| Factor, P.: SQL Code Smells. Redgate, http://assets.red-gate.com/community/books/sql-code-smells.pdf last accessed 2024/12/24 (Using VARCHAR(1), VARCHAR(2), etc). |