1.primary key, unique key 是不是数据库自动建索引 ?
Oracle automatically creates an index for each UNIQUE or PRIMARY KEY declaration.
2. oracle 允许把 foreign key 建在另一个数据库的一张表的primary/unique key 上吗?
of course
I can't answer this question. Basically, I don't think so.
3. A materialized view is a database object that contains the results of a query.They are local copies of data located remotely, or are used to create summary tables based on aggregations of a table's data. Materialized views, which store data based on remote tables are also, know as snapshots.
Oracle automatically creates an index for each UNIQUE or PRIMARY KEY declaration.
2. oracle 允许把 foreign key 建在另一个数据库的一张表的primary/unique key 上吗?
of course
I can't answer this question. Basically, I don't think so.
3. A materialized view is a database object that contains the results of a query.They are local copies of data located remotely, or are used to create summary tables based on aggregations of a table's data. Materialized views, which store data based on remote tables are also, know as snapshots.