mrldb 0.0.3

A library to handle your databases: cassandra, mariadb, (mysql), sqlite3

MrlDB by Rémi "Mr e-RL" LANGDORPH

Copyright (c) 2019 Rémi LANGDORPH - [e-mail] (under MIT license)

Links:

pypi project

github repo

Install with pypi:

pip install mrldb

This package supports the followings database systems: mariadb, mysql, cassandra, sqlite3

Tutorial script:

from mrldb import MrlDBCassandra, MrlDBCluster, mdbcl

we add a simple cassandra cluster as connection to the mrldb cluster, we set cc0 as an alias to the db

mdbcl.add("cassandracluster0", MrlDBCassandra("127.0.0.2"), aliases=["cc0"])

we can add other aliases to this connection:

mdbcl.addalias("cassandracluster0", ["cc0_", "cassandra0", "testcluster"])

you can connect to your host with password and username

mdbcl.add("cassandracluster1", MrlDBCassandra("127.0.0.3", username="admin", password="something"))

you can specify the database too

mdbcl.add("cassandracluster2", MrlDBCassandra("127.0.0.4", database="mydbtest", aliases=["cc3"]))

and the best, you can provide database structure to have advanced features

mdbcl.add("cassandracluster3", MrlDBCassandra("127.0.0.5", database="mydbtest",
structure={"table0": {"col1": "integer unique", "col2": "text"}, "table2": {"name": "text"}}), aliases=["cc3"])

the following examples are working for all the differents database systems

SELECT

with the correct structure, the following command will give you for each records a dict with the col name and the value, (you can replace the columns by a "*"

mdbcl.get("cc3").select(table="table0", columns=["col1"], conds=None)

result= [{"col1": 0}, {"col1": 1}...]

you can use this without structure, it just return the results without dictionnarys

mdbcl.get("cc2").select(table="table0", columns=["col1"], conds=None)

result= [(0, ), (1, )...]

you can use conditions

mdbcl.get("cc3").select(table="table0", columns="*", conds="col2='test'")

result= [{"col1": 0, "col2": "test"}, ...]

INSERT

data is a dict with all the values to insert

mdbcl.get("cc3").insert(table="table0", data={"col1": 5, "col2": "ok"})

UPDATE

use data as the insert command, you can specify conditions with conds

mdbcl.get("cc3").update(table="table0", data={"col1": 5, "col2": "ok"}, conds="col2='test'")

DB init

will create the table (or ignore if exists) as the structure

mdbcl.get("cc3").init()

with structure={"table0": {"col1": "integer unique", "col2": "text"}, "table2": {"name": "text"}}

will execute the following commands:

['CREATE TABLE IF NOT EXISTS table0(col1 integer unique, col2 text)',
 'CREATE TABLE IF NOT EXISTS table2(name text)']

DOCUMENTATION

STRUCTURE

with structure, you can get the column names with the results in a dict for each records

structure is an argument for all the DB classes, it must be a None oject or a dictionnary:

MrlDBCassandra(... ,structure={"table0": {"col1": "integer unique", "col2": "text"}, "table2": {"name": "text"}}, ...)

Imports:

• MrlDBCluster(): a cluster of databases, the last created MrlDBCluster can be accessible via mdbcl

from mrldb import MrlDBCluster, mdbcl
mycluster=MrlDBCluster()

• mdbcl: return the last created MrlDBCluster

print(mdbcl)

• MrlDBCassandra(cluster, db=None, structure=None, username=None, password=None): a cassandra cluster handler, require library cassandra-driver
  • you can use the database you want or don't use it
  • username and passsword are only used with PlainTextAuthProvider, if you've configured users and password for your db, else, we're connecting as anonymous
• MrlDBSqlite(file, structure=None, autocommit=0): a sqlite file handler, require base library sqlite3 (not recommanded)
  • the file is sqlite3 db file
  • autocommit is the time in seconds (can be a float) between each autocommit, disabled if set 0 (by default)
• MrlDBMsql(host, database=None, structure=None, username=None, password=None): a cassandra cluster handler, require library mysql
  • host is the ip adress of the host or a dns-resolvable name of the host
  • you can use the database you want
  • username and passsword are only used with PlainTextAuthProvider, if you've configured users and password for your db, else, we're connecting as anonymous