A tiny and temporary db for quick data cleansing and transformation. It is a high-level Python coding and would help any Pythonistas up to speed with ETL work.
.. contents:: Table of Contents (Click the three dots menu above if in Github) :depth: 2
.. code-block:: python
pip install bintang
.. code-block:: python
from bintang import Bintang # import the package bt = Bintang() # bintang object created
bt.create_table('Person')
print(bt )
Use insert function to populate a table. The parameters are record and columns.
.. code-block:: python
bt.create_table('Person')
bt['Person'].insert([1,'John','Smith','1 Station St'], ['id','name','surname','address']) bt['Person'].insert([2,'Jane','Brown','Digging','8 Parade Rd'], ['id','name','surname','hobby','address']) bt['Person'].insert([3,'Okie','Dokie','7 Ocean Rd'], ['id','name','surname','Address']) bt['Person'].insert((4,'Maria','Digging','7 Heaven Ave'), ('id','name','hobby','Address')) bt['Person'].insert((5,'Bing','Digging',None), ('id','name','hobby','Address'))
bt.create_table("FishingClub") bt['FishingClub'].insert(['Ajes','Freeman','Active'], ['FirstName','LastName','Membership']) bt['FishingClub'].insert(['John','Smith','Active'], ['FirstName','LastName','Membership']) bt['FishingClub'].insert(['Jane','Brown','Active'], ['FirstName','LastName','Membership']) bt['FishingClub'].insert(['Nutmeg','Spaniel','Active'], ['FirstName','LastName','Membership']) bt['FishingClub'].insert(['Zekey','Pokey','Active'], ['FirstName','LastName','Membership'])
Loop your data using iterrows function. This will loop through all the rows one by one in a Python dict.
.. code-block:: python
for idx, row in bt['Person'].iterrows(): print(idx, row)
If the table is small, you can use print() function to output the records to terminal.
.. code-block:: python
Person.print()
You should notice that all columns now have been normalised for each row, even though all records have not used all column names during insertion.
When the 1st record (idx 0) is inserted, four columns created. id, name, age and address.
When insert 4th record is inserted (idx 3), a hobby column added.
Inspect Person table column list. You can also use function table.get_columns() to list all columns.
.. code-block:: python
print(bt['Person'])
Use update function to change the data. The function signature is table.update(column, value, where=None). The value and where parameters can use lambda function argument for smarter expression.
.. code-block:: python
bt['Person'].update('age', 10, where=lambda row: row['name']=='Maria')
Retrieve the row stored at the 3rd index by passing 3 inside the list next to table object.
.. code-block:: python
bt['Person'][3]
We are going to provide some functions that may be needed most when working with Bintang objects.
Read an Excel file and create Bintang tables. The first row will be assumed as column header. Go to Bintang.Table.read_excel() to read a single sheet and populate the data into created table.
:path: an excel file path to read from. :sheetname: a list of sheets that only needed to be read. If not specified all available sheets will be read (default).
.. code-block:: python
bt.read_excel('/path/to/file.xlsx')
Read JSON string and create a table or more according to hierarchy paths contained in json 'object'.
:json_str: a json string :tablepaths: a list of paths which contain a list of objects (equivalent to records).
.. code-block:: python
import bintang import json
json_str = '{"Page:": 100, "Time": "2033-09-05T00:00:00Z",
"Person": [{"id": 1, "name": "John", "surname": "Smith",
"Address": {"number": 1, "street": "Station", "street_type": "Street"}},
{"id": 2, "name": "Jane", "surname": "Brown",
"Address": {"number": 8, "street": "Parade", "street_type": "Road"}}],
"PersonDetails": [{"person_id": "1", "hobby": "Blogging", "is_meat_eater": true},
{"person_id": "2", "hobby": "Reading", "is_meat_eater": null,
"LuckyDays": [13, 17, 19]}]}'
bt = bintang.Bintang('From JSON') bt.read_json(json_str)
print(bt) # show bt tables
for idx, row in bt['/'].iterrows(): print(idx, row)
for idx, row in bt['/Person'].iterrows(): print(idx, row)
bt['/Person/Address'].print()
Please note that since json can contain complex hierarchy paths and still valid (eg. system configuration), then a further transformation is required. A well written JSON can be transformed to Bintang tabular model straight away.
Return one or more columns from lookup table.
:lkp_table: lookup table :on: lookup key tuples :ret_columns: lookup columns to be returned
.. code-block:: python
bt['Person'].blookup('FishingClub')],
[('name','FirstName')],
['Membership'])
for idx, row in bt['Person'].iterrows(['name','Membership']): print(idx, row)
We can see only John and Jane got the membership because their names exists in both tables.
Return grouped rows based upon the value of columns.
:columns: a list of columns that is used to group the data. :drop_none: if True, to drop/exclude the group if all columns hold None. :group_count: if True, create row count from group columns. :group_concat: a column to create group_concat like mysql. :counts: a list of columns to create count column(s) :sums: a list of columns to create sum column(s) :mins: a list of columns to create min column(s) :maxs: a list of columns to create max column(s)
.. code-block:: python
bt.create_table('Product') # this will be our basis table for grouping p = bt['Product'] # assign p as the table p.insert({'id':1, 'brand': 'Shimano', 'class':'rod', 'name':'Extraction','price':299}) p.insert({'id':2, 'brand': 'Shimano', 'class':'rod', 'name':'Zodias Travel','price':399}) p.insert({'id':3, 'brand': 'Ugly Stik', 'class':'rod', 'name':'Balance II','price':63.99}) p.insert({'id':4, 'brand': 'Shimano', 'class':'rod', 'name':'Zodias Travel','price':399}) p.insert({'id':5, 'brand': 'Shimano', 'class':'reel', 'sub class': 'spinning', 'name':'Sedona F1','price':99.00}) p.insert({'id':6, 'brand': 'Shimano', 'class':'reel', 'sub class':'spinning', 'name':'FX Series 4000','price':54.99})
grouped = p.groupby(['brand', 'class'], group_count=True)
grouped.print()
grouped = p.groupby(['brand'], group_concat='id', sums=['price']) # another example
grouped.print()
Return a new table from an inner join operation.
:right_table: name of right table or the second table. :on: a list of pair columns used for the join. :into: a new table name to hold the result. :out_leftcolumns: columns output from left table. If not specified then it will return all columns. :out_rightcolumns: columns outpout from right table. If not specified then it will return all columns.
.. code-block:: python
bt.create_table('Person') # This will be a left table
bt.create_table('FishingClub') # this will be a right table
res = bt.innerjoin('Person' # left table
,'FishingClub' # right table
,[('name','FirstName'), ('surname','LastName')] # on
,into='Fisherman'
,out_lcolumns=['name','address']
,out_rcolumns=['Membership']
)
for idx, row in bt['Fisherman'].iterrows(): print(idx, row)
Insert a record into a table.
:record: a list/tuple of data. Or a dict where key=column, value=record :columns: a list/tuple of columns (in the same order as in the record)
.. code-block:: python
bt.create_table('Person') p = bt.get_table('Person') # get table object for Person
p.insert([1,'John','Smith','1 Station St'], ['id','name','surname','address']) p.insert([2,'Jane','Brown','Digging','8 Parade Rd'], ['id','name','surname','hobby','address']) p.insert([3,'Okie','Dokie','7 Ocean Rd'], ['id','name','surname','Address']) p.insert((4,'Maria','Digging','7 Heaven Ave'), ('id','name','hobby','Address')) p.insert((5,'Bing','Digging',None), ('id','name','hobby','Address'))
bt.create_table('FishingClub')
columns = ['FirstName','LastName','Membership'] bt['FishingClub'].insert(['Ajes','Freeman','Active'], columns) bt['FishingClub'].insert(['John','Smith','Active'], columns) bt['FishingClub'].insert(['John','Brown','Active'], columns) bt['FishingClub'].insert(['Okie','Dokie','Active'], columns) bt['FishingClub'].insert(['Zekey','Pokey','Active'], columns)
bt.create_table("Product") prod = bt['Product']
prod.insert({'id':1, 'name':'Hook','price':1.60}) prod.insert({'id':2, 'name':'Sinker','price':1.20}) prod.insert({'id':3, 'name':'Reels','price':75})
Loop through Bintang table's rows and yield index and row. Row can be called out as dict (default) or list.
:columns: a list of columns to output. If None, will output all columns. :row_type: either 'dict' (default) or 'list'.
.. code-block:: python
for idx, row in bt['tablename'].iterrows(): # do something with idx or row print(idx, row)
Read csv file and populate its records to table.
:path: a csv file path to read from. :delimiter: field seperator, by default it'll accept a comma character. :header_row: the row number that contains column name or label.
.. code-block:: python
bt.create_table('Person') bt['Person'].read('/path/to/file.csv') bt['Person'].print()
Read an Excel file into Bintang table.
:path: an excel file path to read from. :sheetname: the sheetname to read from. :header_row: the row number that contains column name or label.
.. code-block:: python
bt.create_table('Person') bt['Person'].read_excel('/path/to/file.xlsx', 'Sheet1')
Read sql table and populate the data to Bintang table.
:conn: pyodbc database connection :sql_str: sql query, if none it will select * from a same sql table name. :params: sql parameters
.. code-block:: python
import bintang import pyodbc
conn_str = "DRIVER={ODBC Driver 17 for SQL Server};SERVER=localhost;PORT=1443;DATABASE=test;Trusted_Connection=yes;" conn = pyodbc.connect(conn_str) sql_str = "SELECT * FROM Person WHERE LastName=?" params = ('Dokey')
bt = bintang.Bintang() bt.create_table('Person') bt['Person'].read_sql(conn, sql_str, params)
for idx, row in bt['Person'].iterrows(): print(idx, row) # would print {'ID': 3, 'FirstName': 'Okie', 'LastName': 'Dokey', 'address': '7 Ocean Rd'}
conn.close()
Write bintang table to a csv file.
:path: a csv file path to write to. :index: write row index if it sets True. :delimiter: field seperator :quotechar: a character to quote the data :quoting: the csv enum for quoting, csv.QUOTE_MINIMAL or 0, csv.QUOTE_ALL or 1, csv.QUOTE_NONNUMERIC or 2, csv.QUOTE_NONE or 3
Notes: setting quoting parameter properly will provide correct value to be presented in csv even if the value containing a delimiter character.
.. code-block:: python
bt['tablename'].to_csv('/path/to/file.csv')
Write Bintang table to an Excel file.
:path: an excel file path to write to. :index: write row index if it sets True.
.. code-block:: python
bt['tablename'].to_excel('/path/to/file.xlsx')
This is just a placeholder. Python make it easy when serializing a dict object to JSON. Conversion would be done by built-in json.JSONEncoder(). Here an example of using our to_dict() function then use build-in module json to convert/export dict to JSON.
.. code-block:: python
import json
dict_obj = bt['table_name'].to_dict()
json_str = json.dumps(dict_obj)
with open ('myfile.json', 'w') as fp: json.dump(dict_obj, fp) # this would serialise dict_obj into myfile.json
Insert records into sql table. Notes: Currently tested for SQL Server 15 and Postgresql 16. However this function should work with other dbms supported by pyodbc.
:conn: pyodbc database connection :table: the table name in the sql database :columns: If a dictionary then a columns mapping where the key is sql column (destination) and the value is bintang columns (source). If a list, column mapping will be created automatically assuming source columns and destination columns are the same. If not provided it assumes that user wants to insert all the columns from the table. :schema: the schema name the sql table belongs to. :method: 'prep' to use prepared statement (default) or 'string' to use sql string. To avoid sql injection, never use string method when the datasource is external or not known. :max_rows: maximum rows per batch insert. Allowed value would be from 1 to 1000. Insert more then 1 record when using prep require all data in a column to use the same type, otherwise will raise error.
.. code-block:: python
import bintang import pyodbc
bt = bintang.Bintang('my bintang') bt.create_table('Person') person = bt.get_table('Person') person.insert([1,'John','Smith','1 Station St'], ['id','name','surname','address']) person.insert([2,'Jane','Brown','Digging','8 Parade Rd'], ['id','name','surname','address']) person.insert([3,'Okie','Dokey','7 Ocean Rd'], ['id','name','surname','address']) person.insert((4,'Maria','Digging','7 Heaven Ave'), ('id','name','hobby','Address')) person.insert((5,'Bing','Digging',None), ('id','name','hobby','Address'))
columns = {'ID':'id', 'FirstName':'name', 'LastName':'surname', 'Address':'address'}
conn = pyodbc.connect("DRIVER={ODBC Driver 17 for SQL Server};SERVER=localhost;PORT=1443;DATABASE=test;Trusted_Connection=yes;")
ret = person.to_sql(conn, 'Person', columns) print(f'{ret} record(s) affected.') conn.commit() conn.close()
Add a table to Bintang object. Think Bintang is a container of tables.
:table_object: table object is a table created from create_table function.
Create a table inside Bintang object
:name: string to name the table :columns: a list of columns. Bintang can create columns during record insertion (dynamic schema effect).
Drop table from tables container.
:name: table name
.. code-block:: python
bt.drop_table(name)
To rename Bintang object name can be done through normal assignment.
.. code-block:: python
import bintang bt = bintang.Bintang('my db') bt.name = 'your db' # change name from 'my db' to 'your db'
Add a column to table. Bintang can create columns during record insertion (dynamic schema effect).
:column: a string of column name
To delete row(s) that meets where conditions.
:where: a lambda expression
.. code-block:: python
p.delete(lambda row: row['name'].lower()=='john')
Notes: lambda is case-sensitive.
To delete the row at index.
:index: row index
Drop a column from a table.
:column: a string of column name
Return a list of columns.
Return a row at given index.
:index: row index. :columns: a list of specific columns wanted in the row. :row_type: row can be in a 'list' or 'dict' (default)
Return True if index exists otherwise None.
:index: row index.
To rename table name, can be done through normal assignment.
.. code-block:: python
bt['my table'].name = 'your table' # change name from 'my table' to 'your table'
Print rows to terminal in table format. This would be handy if the table can fit into terminal.
:columns: a list of columns to output. If None, will output all columns (default). :show_data_type: if True, will output data type.
.. code-block:: python
Person.print()
Rename column name.
:old_column: the existing column that will be renamed. :new_column: new column name.
To update row(s) in the table
:column: column to be updated. If column does not exist then it will be created (dynamic schema effect). :value: the value to be set for the row(s). Can also use lambda. :where: condition in lambda so which row(s) that needs update.
.. code-block:: python
Person.update('job', 'fisherman') # this will create job column and set value of the rows to 'fisherman'
Person.update('job', 'fisherman', where=lambda row: row['name']=='John')
bt['Person'].update('full name', lambda row: row['name'] + ' ' + row['surname'])
bt['Person'].update('full name', lambda row: row['name'] if row['surname'] is None else row['name'] + ' ' + row['surname'])
To update column's attributes, eg. data_type, column_size and ordinal_position.
:name: the column name :data_type: python data type eg. str, int, float :column_size: string length if data_type is a str :ordinal_position: integer for column order.
Note: At the moment data_type and column_size are used for generating sql table and not used for presenting the data.
To update the row at idx. So only one row will be affected.
:index: row index :column: which column will be updated :value: new value
FAQs
A tiny and temporary db for quick data cleansing and transformation.
We found that bintang demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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