Difference between revisions of "PyLoDStorage"

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Line 33: Line 33:
 
         return listOfDicts
 
         return listOfDicts
 
</source>
 
</source>
 +
The above list of dict anc be stored in a Person table with the following structure:
 +
<uml>
 +
package Royals {
 +
  class Person << Entity >> {
 +
  age : FLOAT
 +
  born : DATE
 +
  lastmodified : TIMESTAMP
 +
  name : TEXT <<PK>>
 +
  numberInLine : INTEGER
 +
  ofAge : BOOLEAN
 +
  wikidataurl : TEXT
 +
  }
 +
}
 +
</uml>
 +
The idea is to derive the necessary DDL and SQL command automatically:
 +
<source lang='sql'>
 +
CREATE TABLE Family(name TEXT PRIMARY KEY,country TEXT,lastmodified TIMESTAMP)
 +
INSERT INTO Family (name,country,lastmodified) values (:name,:country,:lastmodified)
 +
</source>
 +
and use them via simple API
 +
<source lang='python'>
 +
from lodstorage.sample import Sample
 +
from lodstorage.sql import SQLDB, EntityInfo
 +
 +
listOfRecords=Sample.getRoyals()
 +
sqlDB=SQLDB()
 +
entityName='Person'
 +
primaryKey='name'
 +
entityInfo=self.sqlDB.createTable(listOfRecords[:10],entityName,primaryKey)
 +
sqlDB.store(listOfRecords,entityInfo)
 +
resultList=self.sqlDB.queryAll(entityInfo)
 +
</source>
 +
 +
The resultList will be the same as the original listOfRecords.

Revision as of 13:55, 10 September 2020

OsProject

OsProject
edit
id  PyLodStorage
state  
owner  Wolfgang Fahl
title  python List of Dict (Table) Storage library
url  https://github.com/WolfgangFahl/pyLodStorage
version  0.0.4
description  
date  2020/09/10
since  
until  

see also DgraphAndWeaviateTest

List of Dicts = Table

a list of dicts(Hashtables) in python can be interpreted as Table which is suitable to be stored i a relational database like sqlite3

Royals example

 @staticmethod
    def getRoyals():
        listOfDicts=[
            {'name': 'Elizabeth Alexandra Mary Windsor', 'born': Sample.dob('1926-04-21'), 'numberInLine': 0, 'wikidataurl': 'https://www.wikidata.org/wiki/Q9682' },
            {'name': 'Charles, Prince of Wales',         'born': Sample.dob('1948-11-14'), 'numberInLine': 1, 'wikidataurl': 'https://www.wikidata.org/wiki/Q43274' },
            {'name': 'George of Cambridge',              'born': Sample.dob('2013-07-22'), 'numberInLine': 3, 'wikidataurl': 'https://www.wikidata.org/wiki/Q1359041'},
            {'name': 'Harry Duke of Sussex',             'born': Sample.dob('1984-09-15'), 'numberInLine': 6, 'wikidataurl': 'https://www.wikidata.org/wiki/Q152316'}
        ]
        today=date.today()
        for person in listOfDicts:
            born=person['born']
            age=(today - born).days / 365.2425
            person['age']=age
            person['ofAge']=age>=18
            person['lastmodified']=datetime.now()
        return listOfDicts

The above list of dict anc be stored in a Person table with the following structure:

The idea is to derive the necessary DDL and SQL command automatically:

CREATE TABLE Family(name TEXT PRIMARY KEY,country TEXT,lastmodified TIMESTAMP)
INSERT INTO Family (name,country,lastmodified) values (:name,:country,:lastmodified)

and use them via simple API

from lodstorage.sample import Sample
from lodstorage.sql import SQLDB, EntityInfo

 listOfRecords=Sample.getRoyals()
 sqlDB=SQLDB()
 entityName='Person'
 primaryKey='name'
 entityInfo=self.sqlDB.createTable(listOfRecords[:10],entityName,primaryKey)
 sqlDB.store(listOfRecords,entityInfo)
 resultList=self.sqlDB.queryAll(entityInfo)

The resultList will be the same as the original listOfRecords.