| Query goal: | Perhaps the character maximum length has been omitted accidentally, i.e., one wrote VARCHAR instead of VARCHAR(n) where n is the maximum permitted number of characters in the field value. VARCHAR and TEXT are synonyms. |
| 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: | Declare maximum field size (VARCHAR(n)) or declare a CHECK constraint that limits the string length in the column. Field size should be selected so that to prevent possibly incorrect values (absurdly long) and provide information to database users (for instance, developers, various generator programs) about the nature of data in the column. Field size is a part of table predicate and it describes the meaning of data to the system. |
| Data source: | INFORMATION_SCHEMA only |
| SQL query: | Click on query to copy it
SELECT table_schema, table_name, column_name, data_type, character_maximum_length FROM INFORMATION_SCHEMA.columns WHERE data_type = 'character varying' AND character_maximum_length IS NULL 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) ORDER BY character_maximum_length DESC, 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 |
|---|---|
| Field size | Queries of this category provide information about the maximum size of values that can be recorded in column fields |
| 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). |