SQL Loader is a powerful utility in Oracle database that can be used to efficiently load large amounts of data from flat files into database tables. In this blog post, we will explore how to use SQL Loader to load data into temporary tables.

Table of Contents

• Introduction
• Creating temporary tables
• Writing the control file
• Loading data using SQL Loader
• Conclusion

Introduction

Temporary tables serve as a staging area for data manipulation operations, such as data cleansing, validation, and transformation, before loading it into the final destination tables. SQL Loader provides a quick and efficient way to load data into these temporary tables.

Creating temporary tables

Before loading data using SQL Loader, you need to create the temporary tables in your database. Temporary tables can be created using SQL statements like CREATE TABLE with the GLOBAL TEMPORARY clause. These tables are specific to the session and their data is automatically deleted when the session ends.

CREATE GLOBAL TEMPORARY TABLE temp_table (
  id NUMBER,
  name VARCHAR2(100)
);

Writing the control file

The control file is a text file that instructs SQL Loader how to map the data from the flat file to the table columns. It defines the file format, data types, delimiters, and more. Here’s an example of a control file:

LOAD DATA
INFILE 'data_file.csv'
APPEND INTO TABLE temp_table
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
(
  id,
  name
)

In this example, we specify the input file as data_file.csv, define the fields separated by a comma, and specify the columns to load data into.

Loading data using SQL Loader

Once you have the control file and temporary tables ready, you can use SQL Loader to load data into the tables. Open a command prompt or terminal and execute the following command:

sqlldr <username>/<password>@<database> CONTROL=<control_file>.ctl

Replace <username>, <password>, <database>, and <control_file> with the appropriate values. This command will start the SQL Loader process and load data into the temporary tables.

Conclusion

Using SQL Loader to load data into temporary tables is an efficient way to manage data loading tasks. It allows for easy data manipulation and validation before loading the data into the final destination tables. By following the steps outlined in this blog post, you can leverage SQL Loader to handle large data sets effectively.

#hashtags: SQLLoader, DataLoading