| Goal | This query identifies superfluous CHECK constraints by detecting logical subsumption. It targets columns where a generic validation ensuring the trimmed string is not empty (e.g., trim(column) <> '') is rendered redundant by a more specific constraint that enforces a minimum length on the trimmed string (e.g., char_length(trim(column)) > 0). Since a string with a positive length is inherently not empty, the generic check adds no functional value and should be removed to simplify the schema. |
|---|---|
| Type | Problem detection Each row in the result could represent a flaw in the design |
| Reliability | Medium Medium number of false-positive results |
| License | MIT (opens in new tab) |
| Data Source | INFORMATION_SCHEMA+system catalog |
| SQL Query |
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Collections
This query belongs to the following collections:
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 .
| Name | Description |
|---|---|
| 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 . |
Categories
This query is classified under the following categories:
CHECK constraints
Queries of this category provide information about CHECK constraints.
Duplication of implementation elements
Queries of this catergory provide information about the duplication of the database objects.
| Name | Description |
|---|---|
| CHECK constraints | Queries of this category provide information about CHECK constraints. |
| Duplication of implementation elements | Queries of this catergory provide information about the duplication of the database objects. |