Create External Table in Oracle: Guide
You can create an external table in Oracle by following these steps:
- Firstly, it is important to ensure that the database user has the permission to create tables, as well as access external files.
- Create an external table using the CREATE TABLE statement, with the following syntax:
CREATE TABLE external_table_name
(
column1 data_type,
column2 data_type,
...
)
ORGANIZATION EXTERNAL
(
TYPE ORACLE_LOADER
DEFAULT DIRECTORY directory_name
ACCESS PARAMETERS
(
RECORDS DELIMITED BY NEWLINE
FIELDS TERMINATED BY ','
LOCATION ('external_file_name')
)
)
REJECT LIMIT UNLIMITED;
In this case, external_table_name is the name of the external table created, column1 and column2 are the column names and data types of the external table, directory_name is the name of the directory where the external files are located, and external_file_name is the name of the external file.
- In the ACCESS PARAMETERS clause, you can configure parameters such as the format of external files and the delimiter of data.
- When creating an external table, it is important to ensure that the path and format of the external files are consistent with what is specified in the ACCESS PARAMETERS.
- After creating an external table, you can use a SELECT statement to query the data in the external table, which is dynamically loaded from external files.
- If you need to delete an external table, you can use the DROP TABLE statement to delete the external table.