Implementation:Apache Shardingsphere DatabaseMetaDataManager Manage

Knowledge Sources	Apache_Shardingsphere
Domains	Mode_Management, Metadata, DDL
Last Updated	2026-02-10 00:00 GMT

Overview

Synchronized manager for database-level metadata operations including schema, table, and view lifecycle management.

Description

DatabaseMetaDataManager handles all database-level metadata operations with synchronized access. It manages database addition/removal, schema addition/removal, table and view alterations, and schema renaming. When schemas change, it triggers global rule refreshes to keep the runtime state consistent.

Usage

Invoked by change handlers in cluster mode or directly by standalone mode to apply metadata changes received from events or API calls.

Code Reference

Source Location

• Repository: Apache_Shardingsphere
• File: DatabaseMetaDataManager.java
• Lines: 1-199

Signature

@RequiredArgsConstructor
public final class DatabaseMetaDataManager {

    private final MetaDataContexts metaDataContexts;

    public synchronized void addDatabase(String databaseName);
    public synchronized void dropDatabase(String databaseName);
    public synchronized void addSchema(String databaseName, String schemaName);
    public synchronized void dropSchema(String databaseName, String schemaName);
    public synchronized void alterTable(String databaseName, String schemaName, ShardingSphereTable table);
    public synchronized void dropTable(String databaseName, String schemaName, String tableName);
    public synchronized void alterView(String databaseName, String schemaName, ShardingSphereView view);
    public synchronized void dropView(String databaseName, String schemaName, String viewName);
    public synchronized void renameSchema(String databaseName, String fromSchemaName, String toSchemaName);
}

Import

import org.apache.shardingsphere.mode.metadata.manager.database.DatabaseMetaDataManager;

I/O Contract

Inputs

Name	Type	Required	Description
databaseName	String	Yes	Target database name
schemaName	String	Varies	Target schema name
table	ShardingSphereTable	Varies	Table metadata to alter
view	ShardingSphereView	Varies	View metadata to alter

Outputs

Name	Type	Description
void	—	Side effect: updates MetaDataContexts and triggers rule refresh

Usage Examples

DatabaseMetaDataManager manager = metaDataContextManager.getDatabaseMetaDataManager();

// Add a new database
manager.addDatabase("new_db");

// Add a schema
manager.addSchema("new_db", "public");

// Alter a table
manager.alterTable("new_db", "public", updatedTable);

// Drop a schema (also removes from global rules)
manager.dropSchema("new_db", "old_schema");

Related Pages

• Principle:Apache_Shardingsphere_DDL_Metadata_Reload