Run queries on new backends

[theosotr]

investigate if it is possible to run queries on new backends e.g.,

• [ ] Oracle DB https://www.oracle.com/database/technologies/appdev/xe.html,
• [x] MS server https://www.microsoft.com/en-us/sql-server/sql-server-downloads
• [x] CockroachDB https://www.cockroachlabs.com/
• MariaDB https://mariadb.org/ (Most ORMs use MySQL adapter for MariaDB)

[theosotr]

@StefanosChaliasos

[StefanosChaliasos]

We should fill the following table

Backend	Django	Peewee	SqlAlchemy	ActiveRecord	Sequilize
Oracle DB	X	-	X	X (not officially)	-
MS Server	X (not officially)	-	X	X (not officially)	X
Maria DB	X	X	X	X	X
CockroachDB	X (not officialy)	X	X (not officially)	X	X (not officially)

X: Supported

[theosotr]

So it's worth to investigating all backends.

Oracle DB: supported by two well-established ORMS MS Server: supported by sqlalchemy and sequelize Maria DB: supported by the majority of ORMs.

[theosotr]

We can also consider Cockroach https://www.cockroachlabs.com/. This DB is not officially supported by the corresponding ORMs, but by the CockroachDB developers. For example see https://github.com/cockroachdb/sqlalchemy-cockroachdb

Why CockroachDB? Because the researchers of ETH found hundeds of bugs in this DBMS, so I believe that we may also find bugs in their ORM extensions.

[StefanosChaliasos]

All orms (Django,Peewee,SQLAlchemy,ActiveRecord) use the same connectors for mysql and mariadb.

[StefanosChaliasos]

29 Cockroachdb

[StefanosChaliasos]

32 MS SQL

[StefanosChaliasos]

It's complex to support oracledb. I implemented the first steps in this branch.