Package com.onec.schema

Class SchemaDiffEngine

java.lang.Object

com.onec.schema.SchemaDiffEngine

public class SchemaDiffEngine
extends Object

Computes the MigrationPlan that brings the live database in line with the metadata-derived SchemaModel.

Existence (tables, columns) is diffed against the live database via INFORMATION_SCHEMA, so it works on day one against any pre-existing deployment. Type changes are detected by comparing declared types against the previous SchemaSnapshot — exact string comparison of what the metadata declared last time, immune to dialect-specific type reporting. Without a stored snapshot (first boot after upgrading the framework) type changes are invisible; they are picked up once a baseline snapshot exists.

Renames are recognized through previousNames on @Attribute, @Catalog and @Document: when the new name is missing from the database but a former name is present, the plan renames (keeping data) instead of creating fresh.

Anything that can lose data — dropping tables/columns, narrowing a type — is flagged SchemaChange.destructive() and only executed when explicitly allowed. Drops are only proposed for objects the framework knows it used to manage (present in the previous snapshot, or columns of a metadata-managed table); user-created tables are never touched.

Constructor Summary

Constructors

Constructor	Description
SchemaDiffEngine(SqlDialect dialect)

Method Summary

Modifier and Type	Method	Description
MigrationPlan	diff(SchemaModel desired, SchemaSnapshot previous, DatabaseIntrospector.DbState db)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

SchemaDiffEngine

public SchemaDiffEngine(SqlDialect dialect)

Method Details

diff

public MigrationPlan diff(SchemaModel desired,
 SchemaSnapshot previous,
 DatabaseIntrospector.DbState db)