nosqlapi column

In this package we find abstract classes and ODM classes concerning the column database types.

client module

The client module contains the specific classes for column databases and they are based on the core classes.

Client module for column NOSQL database.

class nosqlapi.columndb.client.ColumnBatch(batch, session=None)

Bases: nosqlapi.common.core.Batch, abc.ABC

Column NOSQL database Batch class

class nosqlapi.columndb.client.ColumnConnection(*args, **kwargs)

Bases: nosqlapi.common.core.Connection, abc.ABC

Column NOSQL database Connection class

__init__(*args, **kwargs)

Instantiate Connection object

Parameters

• host – Name of host that contains database

• user – Username for connect to the host

• password – Password for connect to the host

• database – Name of database

• port – Tcp port

• bind_address – Hostname or an IP address for multiple network interfaces

• read_timeout – Timeout for reading from the connection in seconds

• write_timeout – Timeout for writing from the connection in seconds

• ssl – Ssl connection established

• ssl_ca – Ssl CA file specified

• ssl_cert – Ssl certificate file specified

• tls – Tls connection established

• ssl_key – Ssl private key file specified

• ssl_verify_cert – Verify certificate file

• max_allowed_packet – Max size of packet sent to server in bytes

class nosqlapi.columndb.client.ColumnResponse(data, code=None, header=None, error=None)

Bases: nosqlapi.common.core.Response, abc.ABC

Column NOSQL database Response class

__weakref__

list of weak references to the object (if defined)

class nosqlapi.columndb.client.ColumnSelector(*args, **kwargs)

Bases: nosqlapi.common.core.Selector, abc.ABC

Column NOSQL database Selector class

__init__(*args, **kwargs)

Instantiate Selector object

Parameters

• selector – Selector part of the query string

• fields – Return fields

• partition – Partition or collection of data

• condition – Condition of query

• order – Order by specific selector

• limit – Limit result

abstract alias(*args, **kwargs)

Aliases the selector: SELECT col1 AS person

abstract all()

Star selector: SELECT *

abstract cast(*args, **kwargs)

Casts a selector to a type: SELECT CAST(a AS double)

abstract count()

Selects the count of all returned rows: SELECT count(*)

property filtering

Filter data

class nosqlapi.columndb.client.ColumnSession(connection, database=None)

Bases: nosqlapi.common.core.Session, abc.ABC

Column NOSQL database Session class

abstract alter_table(*args, **kwargs)

Alter table or rename

abstract compact(*args, **kwargs)

Compact table or database

abstract create_table(*args, **kwargs)

Create table on database

abstract delete_table(*args, **kwargs)

Create table on database

abstract truncate(*args, **kwargs)

Delete all data into a table

client example

This is an example of a library for connecting to a cassandra server.

# mycolumndb.py
import nosqlapi

# this module is my library of NOSQL column database, like Cassandra database

class Connection(nosqlapi.columndb.ColumnConnection):
    def __init__(host='localhost', port=7000, database=0, username=None, password=None, ssl=None, tls=None,
                 cert=None, ca_cert=None, ca_bundle=None): ...
    def close(self): ...
    def connect(self, *args, **kwargs): ...
    def create_database(self, database): ...
    def has_database(self, database): ...
    def databases(self): ...
    def delete_database(self): ...
    def show_database(self, database): ...


class Session(nosqlapi.columndb.ColumnSession):
    # define here all methods
    pass

conn = Connection('mycassandra.local', 'testdb', username='admin', password='pa$$w0rd', tls=True)
print(conn.show_database('testdb')      # ('testdb', 17983788, 123, False) -- name, size, rows, readonly
sess = conn.connect()                   # Session object
...

odm module

The odm module contains the specific object for column databases.

ODM module for column NOSQL database.

class nosqlapi.columndb.odm.Column(name, data=None, of_type=None, max_len=None, auto_increment=False, primary_key=False, default=None)

Bases: object

Represents column as container of values

__init__(name, data=None, of_type=None, max_len=None, auto_increment=False, primary_key=False, default=None)

Column object

Parameters

name – Name of column

:param data. Data list or tuple :param of_type: Type of column :param max_len: Max length of column :param auto_increment: Boolean value (default False) :param primary_key: Set this column like a primary key :param default: Default function for generate data

__repr__()

Return repr(self).

__str__()

Return str(self).

__weakref__

list of weak references to the object (if defined)

append(data=None)

Appending data to column. If auto_increment is True, the value is incremented automatically.

Parameters

data – Any type of data

Returns

None

property auto_increment

Auto-increment value

property data

List of values

property of_type

Type of column

pop(index=- 1)

Deleting value

Parameters

index – Number of index

Returns

None

class nosqlapi.columndb.odm.Index(name, table, column)

Bases: tuple

__getnewargs__()

Return self as a plain tuple. Used by copy and pickle.

static __new__(_cls, name, table, column)

Create new instance of Index(name, table, column)

__repr__()

Return a nicely formatted representation string

property column

Alias for field number 2

property name

Alias for field number 0

property table

Alias for field number 1

class nosqlapi.columndb.odm.Keyspace(name, exists=False)

Bases: nosqlapi.kvdb.odm.Keyspace

Represents keyspace like database

class nosqlapi.columndb.odm.Table(name, *columns, **options)

Bases: object

Represents table as container of columns

__init__(name, *columns, **options)

Table object

Parameters

• name – Name of table

• columns – Columns

• options – Options

__repr__()

Return repr(self).

__str__()

Return str(self).

__weakref__

list of weak references to the object (if defined)

add_column(*columns)

Adding one or more column object to table

Parameters

columns – Column objects

Returns

None

add_index(index)

Adding index to index property

Parameters

index – Name or Index object

Returns

None

add_row(*rows)

Add one or more row into columns

Parameters

rows – Tuple of objects

Returns

None

property columns

List of columns

delete_column(index=- 1)

Deleting one column to table

Parameters

index – Number of index

Returns

None

delete_index(index=- 1)

Deleting index to index property

Parameters

index – Name or Index object

Returns

None

delete_row(row=- 1)

Delete one row into columns

Parameters

row – Index of row

Returns

None

get_rows()

Getting all rows

Returns

List[tuple]

property index

List of indexes

property name

Name of table

property options

Options

set_option(option)

Update options

Parameters

option – Dict options

Returns

None

nosqlapi.columndb.odm.column(func)

Decorator function to transform list or tuple object to Column object

Parameters

func – function to decorate

Returns

Column object

odm example

These objects represent the respective column in databases.

import nosqlapi
import mycolumndb

keyspace = nosqlapi.columndb.odm.Keyspace('new_db')     # in short -> nosqlapi.columndb.Keyspace('new_db')
# Make columns
id = nosqlapi.columndb.Column('id', of_type=int)
id.auto_increment = True                                # increment automatically
name = nosqlapi.columndb.Column('name', of_type=str)
# Set data
id.append()
name.append('Matteo Guadrini')
# Make table
table = nosqlapi.columndb.Table('peoples', id, name)
# Create Column object from column decorator
@nosqlapi.columndb.column
def salary(file, limit=5000):
    return [line
            for line in open(file, 'rt').readlines()
            if int(line) < 5000]

# Add column to table
table.add_column(id, name, salary('/tmp/salary.log'))
# Add table to keyspace
keyspace.append(table)

# Create database and insert data
mycolumndb.conn.create_database(keyspace)
mycolumndb.sess.create_table(table)
# Insert new data
mycolumndb.sess.insert('people', (None, 'Arthur Dent', 4000))