Loading data with JSON format using SQL Loader.

12 Oct 2023

JSON (JavaScript Object Notation) is a popular format for storing and exchanging data. It is often used in web applications and APIs. If you have a large amount of data in JSON format that you want to load into a database, you can use SQL Loader to accomplish this task efficiently.

In this blog post, we will learn how to load data with JSON format using SQL Loader. We will cover the following topics:

Prerequisites
Creating a Control File
Loading Data Using SQL Loader
Conclusion

Prerequisites

Before we begin, make sure you have the following:

A database installed and running.
SQL Loader installed on your machine. SQL Loader is a command-line tool that comes with Oracle Database.

Creating a Control File

A control file is a text file that specifies how SQL Loader should load data into a table. In our case, we need to create a control file that tells SQL Loader how to handle JSON data.

Here is an example of a control file for loading JSON data:

LOAD DATA
INFILE 'data.json'
APPEND INTO TABLE employees
FIELDS TERMINATED BY ',' 
(
    employee_id EXPRESSION "json_value(:json, '$.employee_id')",
    first_name EXPRESSION "json_value(:json, '$.first_name')",
    last_name EXPRESSION "json_value(:json, '$.last_name')",
    email EXPRESSION "json_value(:json, '$.email')"
)

In this example, we assume that the JSON file is named data.json and the table we want to load the data into is employees. The EXPRESSION clause is used to extract values from the JSON using JSON path expressions.

Loading Data Using SQL Loader

To load data with JSON format using SQL Loader, follow these steps:

Place the JSON file (data.json) in a suitable location accessible by SQL Loader.
Open a command prompt or terminal and navigate to the directory where SQL Loader is installed.
Run the following command to load the data:

sqlldr username/password@database control=control_file.ctl

Replace username, password, database, and control_file.ctl with your own values.

SQL Loader will read the control file (control_file.ctl) and the JSON data file (data.json) and load the data into the specified table.

Conclusion

In this blog post, we have learned how to load data with JSON format using SQL Loader. JSON data can be efficiently loaded into a database using SQL Loader with the help of a control file that specifies the data extraction process.

By using SQL Loader, you can easily import large amounts of JSON data into your database, making it easier to analyze and query the data. This can be particularly useful when dealing with data from web applications or APIs that use JSON as their data interchange format.

#sqlloader #json