WordPress Plugins

Prevent duplicate input value (Unique input field option). Install the "unique-input-wpforms" plugin then an extra option is available from wp-admin.

The Formidable forms "unique input field" option to check whether submitted data is already submitted or not. Prevent duplicate submissions.

The Fluent Forms MySQL database integration plugin (Fluent Forms DB). It saves data to MySQL's separate tables and columns.

The Formidable Forms MySQL integration plugin (Formidable DB) saves entries to the MySQL database.It saves data to MySQL's separate tables and columns.

Contact form 7 database encryption plugin. Encrypt submissions and save them to the wp_db7_forms MySQL table. Download CFDB7 encryption plugin.

Connect WPForms to PostgreSQL database integration plugin (WPForms PGDB).  This plugin saves the submissions to PostgreSQL separate tables and columns.

Save contact form 7 submissions to MongoDB. Download CF7 MongoDB plugin and add MongoDB database credentials from wp-admin.

Connect WordPress WPForms to MySQL Database Integration.  You can save submissions to an internal or external (remote) MySQL database. Develop CRM also.