https://github.com/umihico/microdb

In-memory, Hash-mapping, Disk-writable, Thread-safe database.
https://github.com/umihico/microdb

database python

Last synced: about 2 months ago
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In-memory, Hash-mapping, Disk-writable, Thread-safe database.

• Host: GitHub
• URL: https://github.com/umihico/microdb
• Owner: umihico
• License: mit
• Created: 2018-12-22T11:19:12.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2018-12-24T06:54:25.000Z (about 6 years ago)
• Last Synced: 2024-11-04T23:51:33.952Z (about 2 months ago)
• Topics: database, python
• Language: Python
• Size: 19.5 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# microdb

In-memory, Hash-mapping, Disk-writable, Thread-safe database.  

[![PyPI version](https://badge.fury.io/py/microdb.svg)](https://badge.fury.io/py/microdb)

Installation with pip

```

$ pip install microdb

```

This database works as list of dictionaries.

```

>>> import microdb

>>> mdb = microdb.MicroDB("testdata/mdb.json", partition_keys=['job', 'name'])

>>> mdb.pprint_all()

[{'job': 'clean', 'name': 'Alice', 'status': 'undone'},

 {'job': 'study', 'name': 'Alice', 'status': 'undone'},

 {'job': 'clean', 'name': 'Bob', 'status': 'undone'},

 {'job': 'study', 'name': 'Bob', 'status': 'undone'}]

>>> mdb.pprint_all_as_grid()

[['name', 'status', 'job'],

  ['Alice', 'undone', 'clean'],

  ['Alice', 'undone', 'study'],

  ['Bob', 'undone', 'clean'],

  ['Bob', 'undone', 'study']]

```  

Only 'upsert' method add data, or overwrite if the "key" is already in use.

```

>>> mdb.upsert({'job': 'clean', 'name': 'Alice', 'status': 'finished'})

>>> mdb.upsert({'job': 'clean', 'name': 'Eve', 'status': 'undone'})

>>> mdb.pprint_all()

[{'job': 'clean', 'name': 'Alice', 'status': 'finished'}, # overwritten

 {'job': 'study', 'name': 'Alice', 'status': 'undone'},

 {'job': 'clean', 'name': 'Bob', 'status': 'undone'},

 {'job': 'study', 'name': 'Bob', 'status': 'undone'},

 {'job': 'clean', 'name': 'Eve', 'status': 'undone'}] # new

```  

Key is tupled values of partition_keys. Use 'gen_key' method to see.  

```

>>> # mdb = microdb.MicroDB("testdata/mdb.json", partition_keys=['job', 'name'])

>>> mdb.gen_key({'job': 'clean', 'name': 'Bob', 'what': 'ever'})

('clean', 'Bob')

```

'get' method and 'in' operator as same as dict

```

>>> {'job': 'clean', 'name': 'Bob', 'what': 'ever'} in mdb

True

>>> mdb.get({'job': 'study', 'name': 'Alice','whaat':'everr'})

{'status': 'undone', 'job': 'study', 'name': 'Alice'}

>>> mdb.get({'wrong': 'key'},'when_not_exist') # same as dict.get

'when_not_exist'

```  

Write on disk when you want.

```

>>> mdb.save()

>>> mdb.save_as_grid() # good to reduce amount when all keys are common

$ cat testdata/mdb.json

[['status', 'job', 'name'], ['undone', 'clean', 'Alice'], ['undone', 'study', 'Alice'], ['undone', 'clean', 'Bob'], ['undone', 'study', 'Bob']]

>>> mdb.save('another_file_name.json') # you can write anywhere

$ cat another_file_name.json

[{'job': 'clean', 'name': 'Alice', 'status': 'undone'}, {'job': 'study', 'name': 'Alice', 'status': 'undone'}, {'job': 'clean', 'name': 'Bob', 'status': 'undone'}, {'job': 'study', 'name': 'Bob', 'status': 'undone'}]

```

All operation is already thread-safe by threading.rlock().

In case if you need to block while operations in a row,

```

>>> with mdb.lock():

...    bob_clean_status=mdb.get({'job': 'clean', 'name': 'Bob'})['status']

...    if bob_clean_status != 'finished':

...       mdb.upsert({'job': 'pay_penalty', 'name': 'Bob','status':'undone'})

```