# ALTER

- [ALTER DATABASE](/docs/server/reference/sql-statements/data-definition/alter/alter-database.md): Modify database characteristics. Learn how to change global properties like the default character set and collation for a specific database.
- [ALTER FUNCTION](/docs/server/reference/sql-statements/data-definition/alter/alter-function.md): Change stored function characteristics. This statement allows modifying the security context or comments of a stored function without dropping it.
- [ALTER LOGFILE GROUP](/docs/server/reference/sql-statements/data-definition/alter/alter-logfile-group.md): Understand the support status of this statement. Originally designed for NDB Cluster, it is not currently supported in MariaDB Server.
- [ALTER SERVER](/docs/server/reference/sql-statements/data-definition/alter/alter-server.md): Modify server definitions. Update connection information for external servers defined with CREATE SERVER, primarily used by the Federated engine.
- [ALTER TABLE](/docs/server/reference/sql-statements/data-definition/alter/alter-table.md): Complete ALTER TABLE guide for MariaDB. Complete syntax for modifying columns, indexes, constraints, and table properties with comprehensive examples and.
- [Online Schema Change](/docs/server/reference/sql-statements/data-definition/alter/alter-table/online-schema-change.md): Modify table structures. This guide covers adding columns, changing data types, managing indexes, and other schema changes for existing tables.
- [ALTER TABLESPACE](/docs/server/reference/sql-statements/data-definition/alter/alter-tablespace.md): Understand the status of tablespace management. This statement, originally for NDB, is not supported in MariaDB for InnoDB tablespaces.