What is an Oracle external table?
What is an Oracle external table?
What is an Oracle external table. An external table is a table whose data come from flat files stored outside of the database. Oracle can parse any file format supported by the SQL*Loader.
What is Oracle data Directory?
From Oracle FAQ. An Oracle directory is a database object pointing to a operating system directory on the database server machine for reading and writing files.
What is the use of external table?
External tables allow Oracle to query data that is stored outside the database in flat files. The ORACLE_LOADER driver can be used to access any data stored in any format that can be loaded by SQL*Loader. No DML can be performed on external tables but they can be used for query, join and sort operations.
What is an external table hive?
An external table is a table for which Hive does not manage storage. If you delete an external table, only the definition in Hive is deleted. The data remains. An internal table is a table that Hive manages.
Where is Oracle database stored?
Most Oracle databases store files in a file system, which is a data structure built inside a contiguous disk address space. All operating systems have file managers that allocate and deallocate disk space into files within a file system. A file system enables disk space to be allocated to many files.
What is directory in SQL?
A directory object specifies an alias for a directory on the server file system where external binary file LOBs ( BFILE s) and external table data are located. You can secure access to the BFILE s stored within the directory structure by granting object privileges on the directories to specific users.
Which two are benefits of external tables?
Debugging and support: External tables are equally useful as debugging and support aids. For example, we can create further external tables over logfiles and badfiles to investigate errors easily with SQL. DBAs can also create external tables over critical files such as the alert log.
Can we update external table in Oracle?
About External Tables. Oracle Database allows you read-only access to data in external tables. You can also create views and synonyms for external tables. However, no DML operations ( UPDATE , INSERT , or DELETE ) are possible, and no indexes can be created, on external tables.
What is difference between views and materialized views?
Views are generally used when data is to be accessed infrequently and data in table get updated on frequent basis. On other hand Materialized Views are used when data is to be accessed frequently and data in table not get updated on frequent basis.
