The Object Relational Mapper (ORM) part of SQLAlchemy offers us a way to persist data in a database without the need to write our own SQL statements. Let us look how that works and what rules we need to follow.
Relationships between tables are of little use if we cannot join them in our queries. Let's look at how SQLAlchemy Core creates JOIN statements.
Relational databases are great to protect your data integrity. However, that only works when you tell the database which objects have a relationship. Let us look what SQLAlchemy Core offers us to create foreign keys through metadata.
When we access our database, we most often only want to work with a few specific rows and not the whole table. Let us look how we can use filters in SQLAlchemy Core.
One of the benefits of SQLAlchemy is that it comes with an abstraction for SQL. Let’s find out how a bit of metadata can help us write much less database code.
If you know your SQL and want to use it with Python, SQLAlchemy is a good tool to help you. You can start with plain SQL commands and later move to a higher level of abstraction.
The big challenge for me in learning SQLAlchemy was that it comes with a lot of terms and concepts that you need to know before you can start to understand this toolkit. Some are familiar and work the same way as in other programming languages, while others are an additional level of abstraction that were new for me. To clear things up, I wrote this post to explain the meaning of the most important concepts in SQLAlchemy.
A big gap in my knowledge of Python is how to access a database. Let us look what Python offers to persist data in a relational database like PostgreSQL, SQLite or SQL Server.
Last week I attended my first PyCon US. It was a well-run online event that showed me many interesting things about Python that I had no idea were even possible.
Python is a great fit for maintenance tools. But when they run for a few minutes without any info to the user, one does not know it they are still doing their job or if they stopped. Let us look on a simple way to make your scripts more user friendly.