haip-database 0.1.4
A generic database interface.

# haip.config

[![License](https://img.shields.io/github/license/haipdev/database.svg)](LICENSE)
[![Build Status](https://travis-ci.org/haipdev/database.svg?branch=master)](https://travis-ci.org/haipdev/database)

haip.database is a minimalistic async database interface for Python 3

## Features

* **minimalistic**: *query* and *do*
* **db by name**: reference your database (sessions) per config-name
* **sql templates**: SQL seperated from code. placeholders are escaped automatically.
* **db pools**: db connection pooling
* **dict short notation**: row.fieldname == row['fieldname']
* **db supported**: mysql, oracle, mssql, (ongoing)

## Getting Started

### Installing

```sh
pip install haip-database
```

or from source:

```sh
git clone https://github.com/haipdev/database.git
```

### Usage

#### Config-files

```yaml
databases:
    mysql_test_db:
        type: mysql
        host: host
        port: port
        database: database
        username: username
        password: password
        max_connections: 3
        max_idle_connections: 3

    oracle_test_db:
        type: oracle
        host: host
        port: port
        username: username
        password: password
        service_name: service_name

    mssql_test_db:
        type: mssql
        driver: driver
        host: host
        port: port
        database: TEST
        username: username
        password: password
```

The database is identified by the section-name (e.g. 'mysql_test_db').

##### Common options

* **type**: mysql | oracle
* **host**: hostname/IP of the database server - default='127.0.0.1'
* **port**: port the database server is listening at - default depends on the type (mysql=3306, oracle=1521)
* **username**: username for login
* **password**: password for login
* **autocommit**: true | false - default=true
* **max_connections**: max number of open connections for this database (otherwise you will get DatabasePoolExhaustedExcpetions)
* **max_idle_connections**: max number of open idle connections

##### Mysql options

* **database**: name of the database on the database-server

Prerequisite: python module "mysql_connector"

##### Oracle options

* **service_name**: service-name (higher priority then SID)
* **sid**: sid

Prerequisite: python module "cx_Oracle"

##### MSSQL options

* **driver**: driver definition string e.g. ""{SQL Server}"

Prerequisite: python module "pyodbc"

##### Example

/path-to-my-config-dir/databases.yml

```yaml
databases:
    testdb:
        type: mysql
        username: testuser
        host: 127.0.0.2
```

(optionally you can place e.g. the passwords in seperate files):

/path-to-my-config-dir/dev/databases.yml

```yaml
databases:
    testdb:
        password: testpassword
```

#### Functions

#### Query

> async def query(db_name, query_template, *values, **args)

* *db_name*: the name of the database as defined in the configuration files (main section "databases" - in the example above e.g. "testdb")
* *query_template*: the filename of the template-file containing the SQL query. This file must have the suffix ".sql".
* **values*: values for query placeholders
* ***args*: the template-vars for the query_template jinja template.

This function returns an array of arrays (array of rows).

##### Query example

/path-to-my-config-dir/queries/firstname.sql

```sql
SELECT firstname, lastname
    FROM users
    WHERE firstname = '{{ firstname }}
```

```python
import haip.config as config
import haip.database as database

config.load('/path-to-my-config-dir', 'dev')
rows = await database.query('testdb', 'queries/firstname.sql', firstname='Reinhard')

for row in rows:
    firstname = row[0]
    lastname = row[1]

await database.shutdown()
```

##### shortcuts

> async def query_assoc(db_name, query_template, **args)

Like "query" but returns an array of dicts. e.g. rows[0]['firstname'] or rows[0].firstname

> async def query_first(db_name, query_template, **args)

Like "query" but returns only the first row as dict. e.g. row['firstname'] or row.firstname. If no rows found None will be returned.

#### Insert/Updates

> async def do(db_name, query_template, **args)

Arguments like "query". This function returns the number of rows effected by this statement.

##### Do example

/path-to-my-config-dir/queries/update.sql

```sql
UPDATE users
    SET firstname='Test'
WHERE lastname = '{{ lastname }}
```

```python
import haip.config as config
import haip.database as database

config.load('/path-to-my-config-dir', 'dev')
changes = await database.do('testdb', 'queries/update.sql', lastname='Hainz')

print(f'effected rows: {changes}')
await database.shutdown()
```

#### Procedures

> async def call(db_name, procedure)

* *db_name*: as above
* *procedure*: the name of the procedure to be called

#### Pool shutdown

> async def shutdown()

Close all open connections in the connection pool normally used before closing your application. If you do not close the open connections in the connection pool you will see some warnings on your db servers. So calling this function is not realy necessary but beautifies your code.

## Running the tests

Tests are written using pytest and located in the "tests" directory.

```sh
pytest tests
```

## Contributing

Feel free to use and enhance this project. Pull requests are welcome.

## Authors

* **Reinhard Hainz** - *Initial work* - [haipdev](https://github.com/haipdev)

## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details

## Dependencies

* [haip-config](https://github.com/haipdev/config)
* [haip-template](https://github.com/haipdev/template)