Configuration¶

All you need to get you started is the configuration describing your database connections and passing it to a DatabaseManager instance.

from orator import DatabaseManager

config = {
    'mysql': {
        'driver': 'mysql',
        'host': 'localhost',
        'database': 'database',
        'user': 'root',
        'password': '',
        'prefix': ''
    }
}

db = DatabaseManager(config)

If you have multiple databases configured you can specify which one is the default:

config = {
    'default': 'mysql',
    'mysql': {
        'driver': 'mysql',
        'host': 'localhost',
        'database': 'database',
        'user': 'root',
        'password': '',
        'prefix': ''
    }
}

Read / Write connections¶

Sometimes you may wish to use one database connection for SELECT statements, and another for INSERT, UPDATE, and DELETE statements. Orator makes this easy, and the proper connections will always be used whether you use raw queries, the query builder or the actual ORM

Here is an example of how read / write connections should be configured:

config = {
    'mysql': {
        'read': {
            'host': '192.168.1.1'
        },
        'write': {
            'host': '192.168.1.2'
        },
        'driver': 'mysql',
        'database': 'database',
        'username': 'root',
        'password': '',
        'prefix': ''
    }
}

Note that two keys have been added to the configuration dictionary: read and write. Both of these keys have dictionary values containing a single key: host. The rest of the database options for the read and write connections will be merged from the main mysql dictionary. So, you only need to place items in the read and write dictionaries if you wish to override the values in the main dictionary. So, in this case, 192.168.1.1 will be used as the “read” connection, while 192.168.1.2 will be used as the “write” connection. The database credentials, prefix, character set, and all other options in the main mysql dictionary will be shared across both connections.

Running queries¶

Once you have configured your database connection, you can run queries.

results = db.select('select * from users where id = ?', [1])

db.insert('insert into users (id, name) values (?, ?)', [1, 'John'])

db.update('update users set votes = 100 where name = ?', ['John'])

db.delete('delete from users')

db.statement('drop table users')

Database transactions¶

To run a set of operations within a database transaction, you can use the transaction method which is a context manager:

with db.transaction():
    db.table('users').update({votes: 1})
    db.table('posts').delete()

Sometimes you may need to start a transaction yourself:

db.begin_transaction()

You can rollback a transaction with the rollback method:

db.rollback()

You can also commit a transaction via the commit method:

db.commit()

Accessing connections¶

When using multiple connections, you can access them via the connection() method:

users = db.connection('foo').table('users').get()

You also can access the raw, underlying dbapi connection instance:

db.connection().get_connection()

Sometimes, you may need to reconnect to a given database:

db.reconnect('foo')

If you need to disconnect from the given database, use the disconnect method:

db.disconnect('foo')

Query logging¶

Orator can log all queries that are executed. By default, this is turned off to avoid unnecessary overhead, but if you want to activate it you can either add a log_queries key to the config dictionary:

config = {
    'mysql': {
        'driver': 'mysql',
        'host': 'localhost',
        'database': 'database',
        'username': 'root',
        'password': '',
        'prefix': '',
        'log_queries': True
    }
}

or activate it later on:

db.connection().enable_query_log()

Now, the logger orator.connection.queries will be logging queries at debug level:

Executed SELECT COUNT(*) AS aggregate FROM "users" in 1.18ms

Executed INSERT INTO "users" ("email", "name", "updated_at") VALUES ('foo@bar.com', 'foo', '2015-04-01T22:59:25.810216'::timestamp) RETURNING "id" in 3.6ms

Executed ('SELECT COUNT(*) AS aggregate FROM "users"', []) in 0.12ms

import logging

logger = logging.getLogger('orator.connection.queries')
logger.setLevel(logging.DEBUG)

formatter = logging.Formatter(
    'It took %(elapsed_time)sms to execute the query %(query)s'
)

handler = logging.StreamHandler()
handler.setFormatter(formatter)

logger.addHandler(handler)