When comparing SQL Server Express vs PostgreSQL, the Slant community recommends PostgreSQL for most people. In the question“What are the best relational databases?” PostgreSQL is ranked 1st while SQL Server Express is ranked 7th. The most important reason people chose PostgreSQL is:
PostgreSQL is known to have a very holistic approach to robustness and data integrity which is reflected by it being fully [ACID](https://en.wikipedia.org/wiki/ACID) compliant. PostgreSQL has always been strict about making sure data is valid before allowing it into the database, and there is no way for a client to bypass those checks. Depending on your requirements, ACID compliance might be important.
Ranked in these QuestionsQuestion Ranking
Pro Rich developer tools
SQL Server Express has deep integration with Visual Studio, Visual Web Developer and SQL Server Management allowing for ease-of-use and rich table and query designers. It may be the best choice for someone who develops in the Microsoft environment.
Pro Easily manage SQL Server instances
"Manage SQL Server Express databases with SQL Server Management Studio Express. Connect to local SQL Server Express databases and manage objects with full Object Explorer integration. Write, execute, and test queries by using visual query plans, and access management and maintenance options."
With a variety of versions to choose from the SQL Server Express version is free of charge. It is capable of upgrading to higher tiers, but that requires a fee.
Pro Easy backup and restore
Can be deployed to all editions of SQL Server and Microsoft Azure SQL Database
Pro Fully ACID compliant
PostgreSQL is known to have a very holistic approach to robustness and data integrity which is reflected by it being fully ACID compliant.
PostgreSQL has always been strict about making sure data is valid before allowing it into the database, and there is no way for a client to bypass those checks.
Depending on your requirements, ACID compliance might be important.
Pro High performance
PostgreSQL performance increases with each release, this is also proven by many benchmark tests.
Notable performance features include:
As PostgreSQL only supports one storage engine, it has been able to integrate and optimise it and with the rest of the database. This has resulted in multiple benefits such as the ability to allow different transaction types to co-exist efficiently without the need to select storage engine types once for each table ahead of time.
On the fly data compression resulting in less IO required for reading.
Asynchronous + synchronous Replication.
PostgreSQL supports a asynchronous API for use by client applications. It is reported to increase performance by up to 40% and is not supported by MySQL.
Designed to scale very well with large numbers of cores at high concurrency levels.
Pro Strong community
PostgreSQL has a strong community backing it, with guides, tutorials and support for any kind of problem a developer may have.
Pro Support for JSON data type
JSON data can be stored as a column with optional indexes. In 9.4 (upcoming at the time of this writing), JSONB will be a binary version of JSON that will save space. It's like the best of the NO-SQL world without having to give up ACID and Relationships. This means that cascading deletes can be done in a single Transaction across multiple JSON documents.
Pro Actively developed
Regular fixes and features are released
Pro Support for geographic objects
PostgreSQL can be extended to have geographic object support through PostGIS and allows for location queries to be run through SQL.
Pro Multiple node packages available
There are many packages (like Sequelize) that integrate deeply with the features Postgres offers.
Pro Support Perl and Python for coding stored procedures
Postgres supports popular languages for coding stored procedures, such as Perl and Python. So, you can fairly easy transform just DB-server to reliable Service with complex business logic.
Pro Open Source, powerful and on par with other paid RDBMS'
It is a powerful, open source product that has all the bells and whistles when compared with its costly, proprietary counterparts.
Con Hardware limitations
Maximum number of cores: 4
Maximum memory utilized per instance: 1GB
Maximum size: 10GB
This hardware could be limiting with some high profile apps and sites.
Con Not suited for small apps
Because of it's complexity and power, it may be an overkill to use PostgreSQL in small applications that will not make use of it's full power.