Migrate SQL Server to PostgreSQL Database – Reasons, Challenges & Best Ways

Choosing the right database is as important as managing and organizing data in it. That is why many users and database administrators often migrate SQL Server to PostgreSQL or MySQL databases, depending on their needs and requirements. In this write-up, we will learn about this migration process and how users can migrate the data using CSV and SQL Script files. 

But, before going right to the technical methods, let’s first learn a little more about PostgreSQL and why this migration is preferred by database administrators. 

Why Migrate Data from SQL Server to PostgreSQL? Learning Differences

To know why users migrate their databases, it is important to know what PostgreSQL is. PostgreSQL is an open-source database management system that is used by database administrators to store and manage their data securely. It follows the standard SQL and hence fully supports the basic commands like INSERT, UPDATE, and DELETE. Furthermore, it also supports most of the modern datatypes such as JSON, arrays, and geospatial data. These are some of the features offered by PostgreSQL. Moving on to comparing the other features with SQL Server to understand why users prefer to migrate SQL Server to PostgreSQL in most cases. 

• SQL Server database is designed and owned by Microsoft, whereas PostgreSQL is an open-source database. 
• When it comes to licensing, MS SQL Server has a paid license. PostgreSQL on the other hand, is free to use.
• SQL Server is mainly supported on Windows-based environments; however, PostgreSQL efficiently works on Windows, Linux, and macOS environments. 
• SQL Server has limited support to modern data types (SQL Server 2025 is the only version that supports modern data types). On the other hand, PostgreSQL natively supports JSON and other data types efficiently. 

These are some of the common reasons why users and database administrators choose PostgreSQL over the SQL Server environment. Moving on with the process, we will now take a look at how planning and assessment for this process is initiated. 

Migrate SQL Server to PostgreSQL Process – Requirements & Precautions

Before beginning the process, it is important for the users to know the requirements of the process and also follow the precautionary measures to avoid disasters during the process. We will now take a look at the prerequisites and safety measures of the method for a safer migration. 

Prerequisites for SQL Server database to PostgreSQL Migration 

• It is important to know the SQL Server database along with its tables, views, indexes, stored procedures, functions, etc. 
• Proper permissions to access and export the SQL Server schema, along with data.
• Installation of PostgreSQL on the desired device to migrate SQL Server to PostgreSQL. Configuration and testing of the environment are also important. 
• Sufficient disk space for the exported CSV or SQL Script file and the PostgreSQL setup.
• Proper knowledge regarding supported data types in SQL Server and PostgreSQL databases.
• Proper migration and testing time window to prevent prolonged database downtime. 

Safety Measures to Follow for a Secure Migration

• Before initiating the migration process, it is safer to take a full backup of the complete database. This will help recover data in case something goes wrong.
• Always perform the migration process on a clone or non-production environment. This will prevent any threat or data loss risk in the production database. 
• It is suggested to first convert the schema to test it in PostgreSQL to be completely sure about data migration. 
• Be prepared for rewriting the stored procedures, triggers, and jobs in the PostgreSQL database after migration. 
• After the migration, verify and validate the data again to check whether the data has been successfully migrated.
• There might be situations that demand reversing the migration process; hence, it is expected to have a rollback plan. 

After learning these factors, let’s now move to the methods that will help with this migration process.

How to Migrate Database from SQL Server to PostgreSQL? Top Methods Explained

We will now take a look at the optimal approaches that can help database administrators migrate SQL Server to PostgreSQL without compromising data integrity. There is no direct way for this migration like we have for SQL Server to MySQL migration. So, to proceed with this migration, we first need to export SQL Server as CSV or SQL Script and then import the file in PostgreSQL database. Even though there are a few methods available for this conversion, they are quite technical even for database administrators.

However, with the help of professional solutions like SysTools SQL Recovery Tool, it is efficient to export the required database files to several formats, including .csv and SQL Scripts. In case the database files get damaged or corrupted due to some reasons, this tool is capable of repairing the corruption before saving them to the desired formats. Moving on to the process, let’s now understand how the first phase to migrate SQL Server to PostgreSQL is completed. 

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Phase 1: Export Data to CSV or SQL Script Files – Quick Steps

1. Install and launch the suggested software. Click on the Open Button to add SQL .mdf files.
2. Choose Quick Scan or Advanced Scan to inspect for any corruption in the file.
3. Preview the recovered data and click on the Export tab.
4. Choose a file format to export the data as, CSV or SQL Script.
5. In both options, you will be provided with a selection of database objects to be exported.
6. Select Export Option as With Schema and Data, and then click on the save button.
7. The tool will then ask for a destination to save the files, browse for the location and click OK.

By following these easy and quick steps, the first phase for this migration is completed. Now it’s time to move to the other phases of this migration process. 

Phase 2: Import the Resultant CSV file to PostgreSQL

After conversion of the data and the schema from the SQL Server database, it is now time to import the resultant files to the destination database to migrate SQL Server to PostgreSQL. We will use the pgAdmin tool for this process. Below are the steps to help with the same:

1. The first step is to open pgAdmin and then connect it to the PostgreSQL server. 
2. Next, expand the database and then go to the Schemas option. 
3. Then go to Public and select the Tables option. 
4. Right-click on the target table and then choose the Import/Export data option. 
5. Select the Import option to add the resultant .csv file to the database.
6. Browse the .csv file path and then set the format to CSV to enable the headers for column names in the file.
7. Next, specify the delimiter for the data. Usually, a comma is used. 
8. Click on the OK button to initiate the migrate SQL Server to PostgreSQL database process. 
9. After the import, validate the data to check whether the migration was successful or not. 

These steps will help you import the data into a PostgreSQL database. With this method, users can effectively import the CSV files. To add the SQL Script files, we will now follow the given steps.

1. Open the pgAdmin tool and then connect it to the desired database.
2. Next, go to the Query tool. In the query tool, upload the resultant SQL Script file.
3. Before proceeding with the migration, review the SQL Script for compatibility with PostgreSQL. 
4. Afterwards, execute the script to migrate SQL Server to PostgreSQL server.
5. Validate data after execution to confirm complete data integrity.

With the help of these steps, users will be able to add their SQL Script in the database and can access the data in PostgreSQL as desired. 

Precautionary Steps After PostgreSQL Migration Process

Here are some of the steps that will help users to validate their data after migrate SQL Server to PostgreSQL. 

• Check and validate the number of rows to confirm that no data has been lost during the migration process. 
• For the table and column checks, run data validation checks in the database. 
• Ensure that all the keys: primary keys, foreign keys, and constraints are applied properly. 
• Rebuild Indexes in database and optimize them after the data import in PostgreSQL.
• Test the application queries, report generations, and data/application integrations in the server after migration. 
• Check and review the user permissions in the database to ensure proper access control.
• Monitor the error logs in PostgreSQL to inspect for errors or warnings.

These are some important things to monitor and validate after the migration process has been completed. 

Conclusion

With the help of this write-up, we have discussed how to migrate SQL Server to PostgreSQL in a secure way. Along with the methods, we have also listed the reasons a user might consider switching their server and how this migration helps them. To make the process clearer, we have explained the methods and the steps. Lastly, we have also suggested the best practices to validate the data after migration process.