In which storage does the oracle query table appear?

Oracle tables may appear in the following storage: Data files: store table data and indexes. Temporary table space: stores temporary data. Rollback segment: stores changes in transactions. Undo segment: stores changes from undo operations. Persistence table pool: caches table data to improve performance. InnoDB tablespace: Stores table data in the InnoDB storage engine. External tables: Connect to external data sources and access data through SQL.

#In which storages do Oracle tables appear?

Oracle tables may appear in the following types of storage:

• Data file: The core storage area of ​​the Oracle database, containing table data and index.
• Temporary table space: Used to store temporary data, such as the results of sorting, aggregation, and join operations.
• Rollback segment: Used to store changes made during transaction processing to support rollback and recovery.
• Undo segment: Similar to the rollback segment, it is used to store the changes made by the cancellation operation.
• Persistence table pool: Optimize the performance of frequently accessed tables by caching table data into shared memory.
• InnoDB Table Space: When using the InnoDB storage engine, table data is stored in a table space.
• External Tables: Allows Oracle to connect to external data sources, such as files or a Hadoop data lake. These tables reside in external storage but are accessible through SQL queries.

Detailed description:

• Data files: Each data file corresponds to a specific table space. When the table is created, the data is allocated into data files.
• Temporary table space: Temporary table space allocates a separate area for each session to store temporary data. This data will be cleared when the session ends.
• Rollback segment: Each database has one or more rollback segments. When the transaction commits, the changes are written to the rollback segment. If a rollback is required, these changes can be used to restore the database to its pre-commit state.
• Undo segment: The undo segment is similar to the rollback segment, but is used to cancel operations. For example, if a user accidentally deletes a row, they can use the undo segment to restore the row.
• Persistence table pool: The persistence table pool caches table data into shared memory. When a table is accessed, Oracle will first check whether the data exists in the cache. If present, the data is retrieved from the cache, resulting in faster access.
• InnoDB Table Space: In the InnoDB storage engine, table data is stored in table spaces. Each tablespace can contain multiple tables.
• External Tables: External tables allow Oracle to connect to external data sources, such as files or a Hadoop data lake. The data itself is stored in external storage, but can be accessed via SQL queries, just as the seolah data resides in an Oracle database.

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