This statement alters a schema. You can alter a schema in the following ways:
- With the CHANGE OWNER option, you can assign a schema to another user or role. The schema and all its objects will then belong to the specified user or role.
- You can set a schema quota with the RAW_SIZE_LIMIT option.
- For virtual schema, you can change its properties or refresh its metadata.
- For physical schema: You need to have the system privilege ALTER ANY SCHEMA.
- For virtual schemas: You need to have
- CHANGE OWNER: The system privilege ALTER ANY VIRTUAL SCHEMA.
- SET: System privilege ALTER ANY VIRTUAL SCHEMA, object privilege ALTER on s or the ownership of the schema by the current user or one of its user roles. Additionally, access rights are necessary on the corresponding adapt script.
- REFRESH: System privilege ALTER ANY VIRTUAL SCHEMA or ALTER ANY VIRTUAL SCHEMA REFRESH, object privilege ALTER or REFRESH on s, or the ownership of s by the current user or one of its roles. Additionally, access rights are necessary on the corresponding adapter script.
- This command is not a part of the SQL standard.
- The option RAW_SIZE_LIMIT imposes a limitation on the size of a schema, i.e., the sum of the raw data sizes in bytes of all the objects within the schema. This is similar to quotas within a file system. You can find the raw object sizes in the system table EXA_ALL_OBJECT_SIZES. The value NULL indicates that there is no limit.
- For details about the virtual schema concept, refer to Virtual Schemas section.
- The REFRESH option triggers an update of the metadata of a virtual schema, that is, the underlying objects of the external data source. This update is only done explicitly by this statement, as doing this implicitly while querying the virtual schemas could lead to transaction conflicts for read-only transactions.
Note: To avoid typos while specifying long numbers, we suggest you to use a numerical expression. For example, 128*1024*1024 for 128MB.