Gavin King ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *updated* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiYjQzZjU5OWQ1... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-15549?atlOrigin=eyJpIjoiYjQzZj... ) HHH-15549 ( https://hibernate.atlassian.net/browse/HHH-15549?atlOrigin=eyJpIjoiYjQzZj... ) incorrect DDL mapping DECIMAL -> BOOLEAN on Oracle ( https://hibernate.atlassian.net/browse/HHH-15549?atlOrigin=eyJpIjoiYjQzZj... ) Change By: Gavin King ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) I just stumbled on this buried treasure in {{OracleDialect}}: {code:java}   case Types.DECIMAL: if ( scale == 0 ) { switch ( precision ) { case 1: return jdbcTypeRegistry.getDescriptor( Types.BOOLEAN );{code} Of course, {{precision==1}} means one _decimal_ digit of precision, not one bit. Now UPDATE: So , _just by pure luck OK , _ this doesn’t break anything because in Oracle pre-23c is for reverse engineering I guess , we map {{BOOLEAN}} but it still seems pretty wrong to assume that every {{ number NUMBER (1,0)}} , but by the same token that whole block of code looks just completely pointless is a boolean value and not a one digit decimal. I believe it should be deleted. ( https://hibernate.atlassian.net/browse/HHH-15549#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-15549#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100207- sha1:1c92a42 )