External Tables

In Oracle SQL, external tables provide a way to query data stored outside the database in a flat file. These files can be in various formats such as CSV, text, or XML. External tables allow you to treat external data files as if they were database tables, making it easy to integrate external data into your SQL queries.

1. Create a Directory Object:

The first step is to create a directory object to specify the location of the external files. All the external files will be stored here.

2. Grant Necessary Privileges:

The next step is to grant the necessary privileges to the user. This privilege is only available to SYS user. That means that SYS will have to grant this user this privilege, if the user is not SYS.

3. Create an External Table:

Now, you can create the external table. The external table definition includes the structure of the external file and the location specified by the directory object.

In this example, we are assuming that there is a CSV file named ’employees.csv’ in the specified directory.

4. Query the External Table:

Once the external table is created, you can query it just like any other table in the database.

5. Cleanup (Optional):

If you want to remove the external table and the directory object, you can use the following commands:

https://docs.oracle.com/en/database/oracle/oracle-database/21/sutil/oracle-external-tables-concepts.html#GUID-ACF1D3AA-1D61-4682-AEC5-42C944756E12

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