Query goal: | Find base table columns that have type NUMERIC and the scale is 0, i.e., one can record in the column only integer values. Arithmetic operations are slower in case of the numeric type compared to an integer type. Thus, in order to record integer values, one should use columns with the type SMALLINT, INTEGER, or BIGINT instead of NUMERIC(p,0). |
Query type: | Problem detection (Each row in the result could represent a flaw in the design) |
Query reliability: | High (Few or no false-positive results) |
Query license: | MIT License |
Fixing suggestion: | Change the data type to SMALLINT, INTEGER, or BIGINT. If the column has been defined based on a domain, then change the underlying type of domain. In case changing the type of a domain one has to drop and recreate the domain and associate the recreated domain again with all the columns with which it was previously associated. |
Data source: | INFORMATION_SCHEMA only |
SQL query: | Click on query to copy it
SELECT table_schema, table_name, column_name, data_type, numeric_precision, numeric_scale, CASE WHEN numeric_precision<5 THEN 'SMALLINT' WHEN numeric_precision BETWEEN 5 AND 9 THEN 'INTEGER' ELSE 'BIGINT' END AS suggested_type FROM INFORMATION_SCHEMA.columns WHERE data_type IN ('decimal', 'numeric') 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 (numeric_scale=0) ORDER BY table_schema, table_name, ordinal_position; |
SQL query | Description |
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SELECT format('ALTER TABLE %1$I.%2$I ALTER COLUMN %3$I SET DATA TYPE %4$s;', table_schema, table_name, column_name, CASE WHEN numeric_precision<5 THEN 'SMALLINT' WHEN numeric_precision BETWEEN 5 AND 9 THEN 'INTEGER' ELSE 'BIGINT' END) AS statements FROM INFORMATION_SCHEMA.columns WHERE data_type IN ('decimal', 'numeric') 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 (numeric_scale=0) AND domain_name IS NULL ORDER BY table_schema, table_name, ordinal_position; | Change type of the column if the column is not defined based on a domain. |
Collection name | Collection description |
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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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Data types | Queries of this category provide information about the data types and their usage. |
Performance | Queries of this category provide information about indexes in a database. |
Reference |
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https://dba.stackexchange.com/questions/110880/numeric-vs-integer-for-a-column-size-and-performance |