Specifying the table structure in SQL Loader.

12 Oct 2023

SQL Loader is a powerful tool used to load data from external files into Oracle databases. One crucial aspect of using SQL Loader efficiently is specifying the table structure correctly. In this blog post, we will explore the various options available to define the table structure when using SQL Loader.

Table Structure Options

The table structure can be specified in SQL Loader using the following options:

Positional notation: This option allows you to define each column in the table based on its position in the input file. You need to specify the starting and ending positions of each column.
Delimited data: In this option, columns are defined by delimiters such as commas or tabs. You can specify the delimiter character used in the input file, and SQL Loader will separate the data into respective columns accordingly.
Fixed-length data: In certain cases, data in the input file may have fixed-length fields. With this option, you can define each column’s length, and SQL Loader will extract the data based on the specified lengths.
External table: SQL Loader also provides the option to load data into an external table. An external table is defined in the Oracle database, and the file is accessed directly by the database without inserting the data into a regular table.

Example Usage

To illustrate how to specify the table structure, let’s consider an example where we have an input file containing customer data with columns for name, age, and email. We will use a comma (,) as the delimiter for this example.

LOAD DATA
INFILE 'customer_data.csv'
INTO TABLE customers
FIELDS TERMINATED BY ","
(
    name,
    age,
    email
)

In the above example, we specify the table name using the INTO TABLE clause and the input file customer_data.csv using the INFILE clause. The columns name, age, and email are defined using the FIELDS TERMINATED BY clause.

Conclusion

Specifying the table structure correctly is essential for successful data loading using SQL Loader. By understanding the available options and using them appropriately, you can efficiently load data from external files into your Oracle database. Experiment with the different options mentioned in this blog post to see which one works best for your specific use case.

#sqlloader #databasemanagement