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EMS SQL Manager for Oracle

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External


An external table is a read-only table whose metadata are stored in the database but whose data are stored outside the database. Among other capabilities, external tables let you query data without first loading them into the database.

 

Table properties - External

 

The following type-specific properties can be set for External tables:

 

Type

This value indicates the access driver of the external table. The access driver is the API that interprets the external data for the database. Use the drop-down list to select one of the two access drivers provided by Oracle Database:

ORACLE_LOADER (lets you read table data from an external table and load it into a database);

ORACLE_DATAPUMP (lets you unload data, i.e. read data from a table in the database and insert it into an external table, and then reload it into an Oracle database)

 

Default directory name

Specify a default directory object corresponding to a directory on the file system where the external data sources may reside.

 

Reject limit

Specify how many conversion errors can occur during a query of the external data before an Oracle Database error is returned and the query is aborted, or select DEFAULT from the drop-down list.

 

Parallel

Use this group to specify the degree of parallel access to the external table.

RadioButton Default

RadioButton No parallel (serial execution)

RadioButton Parallel (select a degree of parallelism equal to the number of CPUs available on all participating instances)

 

Degree

Indicates the degree of parallelism, which is the number of parallel threads used in the parallel operation.

 

Locations

Use the Add location btnAddItem and Delete location btnRemoveItem buttons to manage external data sources. Normally, a data source is a file, but not necessarily. It is subject to the access driver to interpret this information in the context of the external data.

 

Click the Access parameters button to call the Access Parameters dialog that allows you to modify the default behavior of the access driver by setting values to the parameters of the access driver for this external table: record and field parameters.

 

 


See also:

Physical Attributes