Stored procedures and functions are commonly used in databases to encapsulate the logic required to retrieve data. In MS SQL, stored procedures are often used as a way to achieve this, but in PostgreSQL, functions are the natural choice. While SQL Server’s T-SQL makes it easy to dynamically determine the result sets returned by a procedure, this is not the case for PostgreSQL.
Unlike the data migration, there is no compete solution to transfer stored procedures, functions and triggers from SQL Server or Azure SQL to PostgreSQL since this is a quite complicated task. This article explores some tips and tricks to help database engineers or other responsible staff migrate source code from SQL Server to PostgreSQL.
If you are migrating from MS SQL or Azure SQL to PostgreSQL and your application uses stored procedures, you will need to re-write them as functions. You should also research best practices for translating stored procedures from SQL Server or Azure SQL to PostgreSQL functions to ensure that you understand both systems and the problem that the respective procedure/function solves, instead of simply converting the syntax.
It is also important to note that there is a difference in how variables are declared in SQL Server stored procedures and Postgres functions. In SQL Server, variables can be declared anywhere, while in PostgreSQL, local variables must be declared at the beginning of the function. This syntax difference requires a change in habit.
Additionally, if your application uses proprietary features of SQL Server, you will need to rewrite those parts of the application that use SQL Server. It is important to have a good understanding of both MSSQL and Postgres before beginning the migration process to ensure that you can properly address any differences in syntax and functionality between the two systems.
Sounds complicated? Then it is reasonable to try special tools that can partially automate migration of stored procedures, functions, triggers and views from SQL Server or Azure SQL to PostgreSQL. One of such tools is SQL Server to PostgreSQL Code Converter developed by Intelligent Converters.
The product has the following capabilities:
- Stored procedures, functions, triggers and views are migrated
- MS SQL built-in functions are converted into PostgreSQL equivalents
- Predefined MS SQL types are mapped into PostgtreSQL
- Reserved words and identifiers are handled into the most intelligent way
- Source code may be extracted either from database directly or form T-SQL script file
Although SQL Server to PostgreSQL Code Converter automates migration of the basic syntax patterns and constructions, some manual post-processing of the output code may be required, especially for large and complicated fragments of the source code.
Visit official site of Intelligent Converters to learn more about SQL Server to PostgreSQL Code Converter.