Behavior Differences Between SQL*Loader and External Tables

This section describes important differences between loading data with external tables, using the ORACLE_LOADER access driver, as opposed to loading data with SQL*Loader conventional and direct path loads. This information does not apply to the ORACLE_DATAPUMP access driver.

Multiple Primary Input Data Files

If there are multiple primary input data files with SQL*Loader loads, then a bad file and a discard file are created for each input data file. With external table loads, there is only one bad file and one discard file for all input data files. If parallel access drivers are used for the external table load, then each access driver has its own bad file and discard file.

Syntax and Data Types

The following are not supported with external table loads:

  • Use of CONTINUEIF or CONCATENATE to combine multiple physical records into a single logical record.

  • Loading of the following SQL*Loader data types: GRAPHIC, GRAPHIC EXTERNAL, and VARGRAPHIC

  • Use of the following database column types: LONG, nested table, VARRAY, REF, primary key REF, and SID

Byte-Order Marks

With SQL*Loader, if a primary data file uses a Unicode character set (UTF8 or UTF16) and it also contains a byte-order mark (BOM), then the byte-order mark is written at the beginning of the corresponding bad and discard files. With external table loads, the byte-order mark is not written at the beginning of the bad and discard files.

Default Character Sets, Date Masks, and Decimal Separator

For fields in a data file, the settings of NLS environment variables on the client determine the default character set, date mask, and decimal separator. For fields in external tables, the database settings of the NLS parameters determine the default character set, date masks, and decimal separator.

Use of the Backslash Escape Character

In SQL*Loader, you can use the backslash (\) escape character to identify a single quotation mark as the enclosure character, as follows:


In external tables, the use of the backslash escape character within a string raises an error. The workaround is to use double quotation marks to identify a single quotation mark as the enclosure character, as follows: