A native Python client for the Vertica database.
Project description
# vertica-python
[](http://badge.fury.io/py/vertica-python)
0.6.x adds python3 support (namedparams support is currently broken in python3, see issue 112)
0.5.x changes the connection method to accept kwargs instead of a dict to be more dbapi compliant.
copy methods improved and consolidated in 0.5.1
0.4.x breaks some of the older query interfaces (row_handler callback, and connection.query).
It replaces the row_handler callback with an iterate() method. Please see examples below
If you are on 0.4.x, please upgrade to 0.4.6 as there are various bug fixes
vertica-python is a native Python adapter for the Vertica (http://www.vertica.com) database.
vertica-python is currently in beta stage; it has been tested for functionality and has a very basic test suite. Please use with caution, and feel free to submit issues and/or pull requests (after running the unit tests).
vertica-python has been tested with Vertica 6.1.2/7.0.0+ and Python 2.7/3.4.
## Installation
If you're using pip >= 1.4 and you don't already have pytz installed:
pip install --pre pytz
To install vertica-python with pip:
pip install vertica-python
To install vertica-python with pip (with optional namedparams dependencies):
# see 'Using named parameters' section below
pip install 'vertica-python[namedparams]'
Source code for vertica-python can be found at:
http://github.com/uber/vertica-python
## Run unit tests
To run the tests, you must have access to a Vertica database. You can
spin one up with Vagrant that uses the default credentials using
`vagrant up`. If you want to run it against an existing database
instead; you can set the environment variables seen in
`tests/test_commons.py`.
Assuming you have [tox](http://tox.readthedocs.io/) installed, all you
have to do is run `tox`. It will run the unit tests using both python 2 and 3.
If you run into an error like:
```ERROR: InterpreterNotFound: python3.4```
Edit the envlist property of tox.ini to use the version of python you have installed (eg py35)
## Usage
**Create connection**
```python
import vertica_python
conn_info = {'host': '127.0.0.1',
'port': 5433,
'user': 'some_user',
'password': 'some_password',
'database': 'a_database',
# 10 minutes timeout on queries
'read_timeout': 600,
# default throw error on invalid UTF-8 results
'unicode_error': 'strict'
# SSL is disabled by default
'ssl': False}
# simple connection, with manual close
connection = vertica_python.connect(**conn_info)
# do things
connection.close()
# using with for auto connection closing after usage
with vertica_python.connect(**conn_info) as connection:
# do things
```
You can pass an `ssl.SSLContext` to `ssl` to customize the SSL connection options. For example,
```python
import vertica_python
import ssl
ssl_context = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
ssl_context.verify_mode = ssl.CERT_REQUIRED
ssl_context.check_hostname = True
ssl_context.load_verify_locations(cafile='/path/to/ca_file.pem')
conn_info = {'host': '127.0.0.1',
'port': 5433,
'user': 'some_user',
'password': 'some_password',
'database': 'a_database',
'ssl': ssl_context}
connection = vertica_python.connect(**conn_info)
```
See more on SSL options [here](https://docs.python.org/2/library/ssl.html).
**Stream query results**:
```python
cur = connection.cursor()
cur.execute("SELECT * FROM a_table LIMIT 2")
for row in cur.iterate():
print(row)
# [ 1, 'some text', datetime.datetime(2014, 5, 18, 6, 47, 1, 928014) ]
# [ 2, 'something else', None ]
```
Streaming is recommended if you want to further process each row, save the results in a non-list/dict format (e.g. Pandas DataFrame), or save the results in a file.
**In-memory results as list**:
```python
cur = connection.cursor()
cur.execute("SELECT * FROM a_table LIMIT 2")
cur.fetchall()
# [ [1, 'something'], [2, 'something_else'] ]
```
**In-memory results as dictionary**:
```python
cur = connection.cursor('dict')
cur.execute("SELECT * FROM a_table LIMIT 2")
cur.fetchall()
# [ {'id': 1, 'value': 'something'}, {'id': 2, 'value': 'something_else'} ]
connection.close()
```
**Query using named parameters**:
```python
# Using named parameter bindings requires psycopg2>=2.5.1 which is not includes with the base vertica_python requirements.
cur = connection.cursor()
cur.execute("SELECT * FROM a_table WHERE a = :propA b = :propB", {'propA': 1, 'propB': 'stringValue'})
cur.fetchall()
# [ [1, 'something'], [2, 'something_else'] ]
```
**Insert and commits** :
```python
cur = connection.cursor()
# inline commit
cur.execute("INSERT INTO a_table (a, b) VALUES (1, 'aa'); commit;")
# commit in execution
cur.execute("INSERT INTO a_table (a, b) VALUES (1, 'aa')")
cur.execute("INSERT INTO a_table (a, b) VALUES (2, 'bb')")
cur.execute("commit;")
# connection.commit()
cur.execute("INSERT INTO a_table (a, b) VALUES (1, 'aa')")
connection.commit()
```
**Copy** :
```python
cur = connection.cursor()
cur.copy("COPY test_copy (id, name) from stdin DELIMITER ',' ", csv)
```
Where `csv` is either a string or a file-like object (specifically, any object with a `read()` method). If using a file, the data is streamed.
## Rowcount oddities
vertica_python behaves a bit differently than dbapi when returning rowcounts.
After a select execution, the rowcount will be -1, indicating that the row count is unknown. The rowcount value will be updated as data is streamed.
```python
cur.execute('SELECT 10 things')
cur.rowcount == -1 # indicates unknown rowcount
cur.fetchone()
cur.rowcount == 1
cur.fetchone()
cur.rowcount == 2
cur.fetchall()
cur.rowcount == 10
```
After an insert/update/delete, the rowcount will be returned as a single element row:
```python
cur.execute("DELETE 3 things")
cur.rowcount == -1 # indicates unknown rowcount
cur.fetchone()[0] == 3
```
## Nextset
If you execute multiple statements in a single call to execute(), you can use cursor.nextset() to retrieve all of the data.
```python
cur.execute('SELECT 1; SELECT 2;')
cur.fetchone()
# [1]
cur.fetchone()
# None
cur.nextset()
# True
cur.fetchone()
# [2]
cur.fetchone()
# None
cur.nextset()
# None
```
## UTF-8 encoding issues
While Vertica expects varchars stored to be UTF-8 encoded, sometimes invalid strings get into the database. You can specify how to handle reading these characters using the unicode_error connection option. This uses the same values as the unicode type (https://docs.python.org/2/library/functions.html#unicode)
```python
cur = vertica_python.Connection({..., 'unicode_error': 'strict'}).cursor()
cur.execute(r"SELECT E'\xC2'")
cur.fetchone()
# caught 'utf8' codec can't decode byte 0xc2 in position 0: unexpected end of data
cur = vertica_python.Connection({..., 'unicode_error': 'replace'}).cursor()
cur.execute(r"SELECT E'\xC2'")
cur.fetchone()
# �
cur = vertica_python.Connection({..., 'unicode_error': 'ignore'}).cursor()
cur.execute(r"SELECT E'\xC2'")
cur.fetchone()
#
```
## License
MIT License, please see `LICENSE` for details.
## Acknowledgements
Many thanks go to the contributors to the Ruby Vertica gem (https://github.com/sprsquish/vertica), since they did all of the wrestling with Vertica's protocol and have kept the gem updated. They are:
* [Matt Bauer](http://github.com/mattbauer)
* [Jeff Smick](http://github.com/sprsquish)
* [Willem van Bergen](http://github.com/wvanbergen)
* [Camilo Lopez](http://github.com/camilo)
[](http://badge.fury.io/py/vertica-python)
0.6.x adds python3 support (namedparams support is currently broken in python3, see issue 112)
0.5.x changes the connection method to accept kwargs instead of a dict to be more dbapi compliant.
copy methods improved and consolidated in 0.5.1
0.4.x breaks some of the older query interfaces (row_handler callback, and connection.query).
It replaces the row_handler callback with an iterate() method. Please see examples below
If you are on 0.4.x, please upgrade to 0.4.6 as there are various bug fixes
vertica-python is a native Python adapter for the Vertica (http://www.vertica.com) database.
vertica-python is currently in beta stage; it has been tested for functionality and has a very basic test suite. Please use with caution, and feel free to submit issues and/or pull requests (after running the unit tests).
vertica-python has been tested with Vertica 6.1.2/7.0.0+ and Python 2.7/3.4.
## Installation
If you're using pip >= 1.4 and you don't already have pytz installed:
pip install --pre pytz
To install vertica-python with pip:
pip install vertica-python
To install vertica-python with pip (with optional namedparams dependencies):
# see 'Using named parameters' section below
pip install 'vertica-python[namedparams]'
Source code for vertica-python can be found at:
http://github.com/uber/vertica-python
## Run unit tests
To run the tests, you must have access to a Vertica database. You can
spin one up with Vagrant that uses the default credentials using
`vagrant up`. If you want to run it against an existing database
instead; you can set the environment variables seen in
`tests/test_commons.py`.
Assuming you have [tox](http://tox.readthedocs.io/) installed, all you
have to do is run `tox`. It will run the unit tests using both python 2 and 3.
If you run into an error like:
```ERROR: InterpreterNotFound: python3.4```
Edit the envlist property of tox.ini to use the version of python you have installed (eg py35)
## Usage
**Create connection**
```python
import vertica_python
conn_info = {'host': '127.0.0.1',
'port': 5433,
'user': 'some_user',
'password': 'some_password',
'database': 'a_database',
# 10 minutes timeout on queries
'read_timeout': 600,
# default throw error on invalid UTF-8 results
'unicode_error': 'strict'
# SSL is disabled by default
'ssl': False}
# simple connection, with manual close
connection = vertica_python.connect(**conn_info)
# do things
connection.close()
# using with for auto connection closing after usage
with vertica_python.connect(**conn_info) as connection:
# do things
```
You can pass an `ssl.SSLContext` to `ssl` to customize the SSL connection options. For example,
```python
import vertica_python
import ssl
ssl_context = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
ssl_context.verify_mode = ssl.CERT_REQUIRED
ssl_context.check_hostname = True
ssl_context.load_verify_locations(cafile='/path/to/ca_file.pem')
conn_info = {'host': '127.0.0.1',
'port': 5433,
'user': 'some_user',
'password': 'some_password',
'database': 'a_database',
'ssl': ssl_context}
connection = vertica_python.connect(**conn_info)
```
See more on SSL options [here](https://docs.python.org/2/library/ssl.html).
**Stream query results**:
```python
cur = connection.cursor()
cur.execute("SELECT * FROM a_table LIMIT 2")
for row in cur.iterate():
print(row)
# [ 1, 'some text', datetime.datetime(2014, 5, 18, 6, 47, 1, 928014) ]
# [ 2, 'something else', None ]
```
Streaming is recommended if you want to further process each row, save the results in a non-list/dict format (e.g. Pandas DataFrame), or save the results in a file.
**In-memory results as list**:
```python
cur = connection.cursor()
cur.execute("SELECT * FROM a_table LIMIT 2")
cur.fetchall()
# [ [1, 'something'], [2, 'something_else'] ]
```
**In-memory results as dictionary**:
```python
cur = connection.cursor('dict')
cur.execute("SELECT * FROM a_table LIMIT 2")
cur.fetchall()
# [ {'id': 1, 'value': 'something'}, {'id': 2, 'value': 'something_else'} ]
connection.close()
```
**Query using named parameters**:
```python
# Using named parameter bindings requires psycopg2>=2.5.1 which is not includes with the base vertica_python requirements.
cur = connection.cursor()
cur.execute("SELECT * FROM a_table WHERE a = :propA b = :propB", {'propA': 1, 'propB': 'stringValue'})
cur.fetchall()
# [ [1, 'something'], [2, 'something_else'] ]
```
**Insert and commits** :
```python
cur = connection.cursor()
# inline commit
cur.execute("INSERT INTO a_table (a, b) VALUES (1, 'aa'); commit;")
# commit in execution
cur.execute("INSERT INTO a_table (a, b) VALUES (1, 'aa')")
cur.execute("INSERT INTO a_table (a, b) VALUES (2, 'bb')")
cur.execute("commit;")
# connection.commit()
cur.execute("INSERT INTO a_table (a, b) VALUES (1, 'aa')")
connection.commit()
```
**Copy** :
```python
cur = connection.cursor()
cur.copy("COPY test_copy (id, name) from stdin DELIMITER ',' ", csv)
```
Where `csv` is either a string or a file-like object (specifically, any object with a `read()` method). If using a file, the data is streamed.
## Rowcount oddities
vertica_python behaves a bit differently than dbapi when returning rowcounts.
After a select execution, the rowcount will be -1, indicating that the row count is unknown. The rowcount value will be updated as data is streamed.
```python
cur.execute('SELECT 10 things')
cur.rowcount == -1 # indicates unknown rowcount
cur.fetchone()
cur.rowcount == 1
cur.fetchone()
cur.rowcount == 2
cur.fetchall()
cur.rowcount == 10
```
After an insert/update/delete, the rowcount will be returned as a single element row:
```python
cur.execute("DELETE 3 things")
cur.rowcount == -1 # indicates unknown rowcount
cur.fetchone()[0] == 3
```
## Nextset
If you execute multiple statements in a single call to execute(), you can use cursor.nextset() to retrieve all of the data.
```python
cur.execute('SELECT 1; SELECT 2;')
cur.fetchone()
# [1]
cur.fetchone()
# None
cur.nextset()
# True
cur.fetchone()
# [2]
cur.fetchone()
# None
cur.nextset()
# None
```
## UTF-8 encoding issues
While Vertica expects varchars stored to be UTF-8 encoded, sometimes invalid strings get into the database. You can specify how to handle reading these characters using the unicode_error connection option. This uses the same values as the unicode type (https://docs.python.org/2/library/functions.html#unicode)
```python
cur = vertica_python.Connection({..., 'unicode_error': 'strict'}).cursor()
cur.execute(r"SELECT E'\xC2'")
cur.fetchone()
# caught 'utf8' codec can't decode byte 0xc2 in position 0: unexpected end of data
cur = vertica_python.Connection({..., 'unicode_error': 'replace'}).cursor()
cur.execute(r"SELECT E'\xC2'")
cur.fetchone()
# �
cur = vertica_python.Connection({..., 'unicode_error': 'ignore'}).cursor()
cur.execute(r"SELECT E'\xC2'")
cur.fetchone()
#
```
## License
MIT License, please see `LICENSE` for details.
## Acknowledgements
Many thanks go to the contributors to the Ruby Vertica gem (https://github.com/sprsquish/vertica), since they did all of the wrestling with Vertica's protocol and have kept the gem updated. They are:
* [Matt Bauer](http://github.com/mattbauer)
* [Jeff Smick](http://github.com/sprsquish)
* [Willem van Bergen](http://github.com/wvanbergen)
* [Camilo Lopez](http://github.com/camilo)
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