SqlAlchemy table name reflection using an efficient method

Question

I am using the code below to extract table names on a database at a GET call in a Flask app.:

session = db.session()
qry = session.query(models.BaseTableModel) 
results = session.execute(qry)
table_names = []
for row in results:
    for column, value in row.items():
        #this seems like a bit of a hack
        if column == "tables_table_name":
            table_names.append(value)
print('{0}: '.format(table_names))

Given that tables in the database may added/deleted regularly, is the code above an efficient and reliable way to get the names of tables in a database?

Generally when trying to optimize something you should follow this flow: 1. measure performance, 2. if not satisfied with performance go to (3) else exit. 3. find and apply optimizations and go to (1). Doing (3) without doing (1) and (2) is bad, since you will very likely end up with antipattern called premature optimization. — Yaroslav Admin
– Yaroslav Admin, Commented Dec 31, 2016 at 12:08
@YaroslavAdmin Thanks, that will save a few lines of code and probably a bit of execution time. I was wondering if the sqlalchemy methodology used is best practice for my goal? — Don Smythe
– Don Smythe, Commented Dec 31, 2016 at 12:10
BaseTableModel is not a SQLAlchemy thing, right? It's just a table you created? If so, doing plain select is probably the fastest approach you can get. — Yaroslav Admin
– Yaroslav Admin, Commented Dec 31, 2016 at 12:15
@YaroslavAdmin BaseTableModel inherits from the Model object Flask Appbuilder which in turn inherits from SqlAlchemy but I am not clear on exactly what is going on with FAB behind the scenes. — Don Smythe
– Don Smythe, Commented Dec 31, 2016 at 12:52

Yaroslav Admin · Accepted Answer · 2016-12-31 13:01:16Z

1

One obvious optimization is to use row["tables_table_name"] instead of second loop.

Assuming that BaseTableModel is a table, which contains names of all other tables, than you're using the fastest approach to get this data.

answered Dec 31, 2016 at 13:01

Yaroslav Admin

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