Merge pull request oracle-samples#14 from OsBlaineOra/master

Added CRUD examples for Python

Author: Christopher Jones

python/CRUD-examples/README.md

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+The scripts in this directory follow the [BASIC CRUD OPERATIONS USING CX_ORACLE](https://learncodeshare.net/2015/06/02/basic-crud-operations-using-cx_oracle/) tutorial found on [LearnCodeShare.net](https://learncodeshare.net). The examples are written with Python 3 but they should be easily converted to Python 2.

python/CRUD-examples/createDBObjects.sql

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+# code Sample from the tutorial at https://learncodeshare.net/2015/06/02/basic-crud-operations-using-cx_oracle/
+# The following creates and populates the tables used for the tutorial
+# These scripts use identity columns available in Oracle 12.1. If you are using an older version you will need
+# to add your own trigger/sequence functionality to generate the id values.
+
+CREATE TABLE lcs_people (
+ id NUMBER GENERATED BY DEFAULT AS identity,
+ name VARCHAR2(20),
+ age NUMBER,
+ notes VARCHAR2(100)
+)
+/
+
+ALTER TABLE LCS_PEOPLE
+ADD CONSTRAINT PK_LCS_PEOPLE PRIMARY KEY ("ID")
+/
+
+CREATE TABLE LCS_PETS (
+ id NUMBER GENERATED BY DEFAULT AS IDENTITY,
+ name VARCHAR2(20),
+ owner NUMBER,
+ type VARCHAR2(100)
+)
+/
+
+ALTER TABLE LCS_PETS ADD CONSTRAINT PK_LCS_PETS PRIMARY KEY ("ID")
+/
+
+ALTER TABLE LCS_PETS ADD CONSTRAINT FK_LCS_PETS_OWNER FOREIGN KEY ("OWNER") REFERENCES "LCS_PEOPLE" ("ID")
+/
+
+INSERT INTO lcs_people (name, age, notes)
+ VALUES ('Bob', 35, 'I like dogs')
+/
+
+INSERT INTO lcs_people (name, age, notes)
+ VALUES ('Kim', 27, 'I like birds')
+/
+
+INSERT INTO lcs_pets (name, owner, type)
+ VALUES ('Duke', 1, 'dog')
+/
+
+INSERT INTO lcs_pets (name, owner, type)
+ VALUES ('Pepe', 2, 'bird')
+/
+
+COMMIT
+/

python/CRUD-examples/delete/extra_fun_1.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Extra Fun 1"
+# Using the base template, the example code executes a simple delete using named bind variables.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+
+def get_all_rows(label, data_type='people'):
+ # Query all rows
+ cur = con.cursor()
+ if (data_type == 'pets'):
+ statement = 'select id, name, owner, type from lcs_pets order by owner, id'
+ else:
+ statement = 'select id, name, age, notes from lcs_people order by id'
+ cur.execute(statement)
+ res = cur.fetchall()
+ print(label + ': ')
+ print (res)
+ print(' ')
+ cur.close()
+
+get_all_rows('Original Data', 'pets')
+
+cur = con.cursor()
+statement = 'delete from lcs_pets where type = :type'
+cur.execute(statement, {'type':'bird'})
+con.commit()
+
+get_all_rows('New Data', 'pets')

python/CRUD-examples/delete/extra_fun_2.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Extra Fun 2"
+# Using the base template, the example code executes two simple deletes using named bind variables.
+# The child records are removed, followed by the parent record.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+
+def get_all_rows(label, data_type='people'):
+ # Query all rows
+ cur = con.cursor()
+ if (data_type == 'pets'):
+ statement = 'select id, name, owner, type from lcs_pets order by owner, id'
+ else:
+ statement = 'select id, name, age, notes from lcs_people order by id'
+ cur.execute(statement)
+ res = cur.fetchall()
+ print(label + ': ')
+ print (res)
+ print(' ')
+ cur.close()
+
+get_all_rows('Original People Data', 'people')
+get_all_rows('Original Pet Data', 'pets')
+
+cur = con.cursor()
+
+statement = 'delete from lcs_pets where owner = :owner'
+cur.execute(statement, {'owner':5})
+
+statement = 'delete from lcs_people where id = :id'
+cur.execute(statement, {'id':5})
+con.commit()
+
+get_all_rows('New People Data', 'people')
+get_all_rows('New Pet Data', 'pets')

python/CRUD-examples/delete/foreign_keys.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Deleting records referenced by Foreign Keys" 1st example
+# Using the base template, the example code executes a simple delete using named bind variables.
+# When following the tutorial with default data this section intentionally throws an error
+# to demonstrate foreign key functionality.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+
+def get_all_rows(label, data_type='people'):
+ # Query all rows
+ cur = con.cursor()
+ if (data_type == 'pets'):
+ statement = 'select id, name, owner, type from lcs_pets order by owner, id'
+ else:
+ statement = 'select id, name, age, notes from lcs_people order by id'
+ cur.execute(statement)
+ res = cur.fetchall()
+ print(label + ': ')
+ print (res)
+ print(' ')
+ cur.close()
+
+get_all_rows('Original People Data', 'people')
+get_all_rows('Original Pet Data', 'pets')
+
+cur = con.cursor()
+statement = 'delete from lcs_people where id = :id'
+cur.execute(statement, {'id':1})
+con.commit()
+
+get_all_rows('New People Data', 'people')
+get_all_rows('New Pet Data', 'pets')

python/CRUD-examples/delete/handle_pets.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Deleting records referenced by Foreign Keys" 2nd example
+# Using the base template, the example code executes two simple deletes using named bind variables.
+# The child records are removed, followed by the parent record.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+
+def get_all_rows(label, data_type='people'):
+ # Query all rows
+ cur = con.cursor()
+ if (data_type == 'pets'):
+ statement = 'select id, name, owner, type from lcs_pets order by owner, id'
+ else:
+ statement = 'select id, name, age, notes from lcs_people order by id'
+ cur.execute(statement)
+ res = cur.fetchall()
+ print(label + ': ')
+ print (res)
+ print(' ')
+ cur.close()
+
+get_all_rows('Original People Data', 'people')
+get_all_rows('Original Pet Data', 'pets')
+
+cur = con.cursor()
+
+statement = 'update lcs_pets set owner = :new_owner where owner = :old_owner'
+cur.execute(statement, {'new_owner':2, 'old_owner':1})
+
+statement = 'delete from lcs_people where id = :id'
+cur.execute(statement, {'id':1})
+con.commit()
+
+get_all_rows('New People Data', 'people')
+get_all_rows('New Pet Data', 'pets')

python/CRUD-examples/delete/reset_data.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Resetting the data"
+# The following resets the data for use with the update section
+# For both tables:
+# Table data is removed.
+# The identity column is set to start with the id after the starting data.
+# Using the executemany function an array of starting data is inserted into the table.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+cur = con.cursor()
+
+# Delete rows
+statement = 'delete from lcs_pets'
+cur.execute(statement)
+
+# Reset Identity Coulmn
+statement = 'alter table lcs_pets modify id generated BY DEFAULT as identity (START WITH 8)'
+cur.execute(statement)
+
+# Delete rows
+statement = 'delete from lcs_people'
+cur.execute(statement)
+
+# Reset Identity Coulmn
+statement = 'alter table lcs_people modify id generated BY DEFAULT as identity (START WITH 8)'
+cur.execute(statement)
+
+# Insert default rows
+rows = [{'id':1, 'name':'Bob', 'age':35, 'notes':'I like dogs'},
+ {'id':2, 'name':'Kim', 'age':27, 'notes':'I like birds'},
+ {'id':3, 'name':'Cheryl', 'age':23, 'notes':'I like horses'},
+ {'id':4, 'name':'Bob', 'age':27, 'notes':'I like rabbits'},
+ {'id':5, 'name':'Stacey', 'age':45, 'notes':'I like snakes'},
+ {'id':6, 'name':'Pete', 'age':23, 'notes':'I like cats'},
+ {'id':7, 'name':'Pat', 'age':36, 'notes':'I like dogs'}]
+cur.bindarraysize = 2
+cur.executemany("insert into lcs_people(id, name, age, notes) values (:id, :name, :age, :notes)", rows)
+con.commit()
+
+# Insert default rows
+rows = [{'id':1, 'name':'Duke', 'owner':1, 'type':'dog'},
+ {'id':2, 'name':'Dragon', 'owner':2, 'type':'bird'},
+ {'id':3, 'name':'Sneaky', 'owner':5, 'type':'snake'},
+ {'id':4, 'name':'Red', 'owner':2, 'type':'bird'},
+ {'id':5, 'name':'Red', 'owner':3, 'type':'horse'},
+ {'id':6, 'name':'Buster', 'owner':1, 'type':'dog'},
+ {'id':7, 'name':'Fido', 'owner':7, 'type':'cat'}]
+cur.bindarraysize = 2
+cur.executemany("insert into lcs_pets (id, name, owner, type) values (:id, :name, :owner, :type)", rows)
+con.commit()
+
+cur.close()

python/CRUD-examples/delete/simple.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Simple delete"
+# Using the base template, the example code executes a simple delete using named bind variables.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+
+def get_all_rows(label, data_type='people'):
+ # Query all rows
+ cur = con.cursor()
+ if (data_type == 'pets'):
+ statement = 'select id, name, owner, type from lcs_pets order by owner, id'
+ else:
+ statement = 'select id, name, age, notes from lcs_people order by id'
+ cur.execute(statement)
+ res = cur.fetchall()
+ print(label + ': ')
+ print (res)
+ print(' ')
+ cur.close()
+
+get_all_rows('Original Data', 'pets')
+
+cur = con.cursor()
+statement = 'delete from lcs_pets where id = :id'
+cur.execute(statement, {'id':1})
+con.commit()
+
+get_all_rows('New Data', 'pets')

python/CRUD-examples/delete/template.py

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+# Code Sample from the tutorial at https://learncodeshare.net/2015/07/09/delete-crud-using-cx_oracle/
+# section titled "Boilerplate template"
+# The following code is used as the base template for the other examples.
+
+import cx_Oracle
+import os
+connectString = os.getenv('DB_CONNECT') # The environment variable for the connect string: DB_CONNECT=user/password@database
+con = cx_Oracle.connect(connectString)
+
+def get_all_rows(label, data_type='people'):
+ # Query all rows
+ cur = con.cursor()
+ if (data_type == 'pets'):
+ statement = 'select id, name, owner, type from lcs_pets order by owner, id'
+ else:
+ statement = 'select id, name, age, notes from lcs_people order by id'
+ cur.execute(statement)
+ res = cur.fetchall()
+ print(label + ': ')
+ print (res)
+ print(' ')
+ cur.close()
+
+get_all_rows('Original Data', 'pets')
+
+# Your code here
+
+get_all_rows('New Data', 'pets')

python/CRUD-examples/dropDBObjects.sql

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+# code Sample from the tutorial at https://learncodeshare.net/2015/06/02/basic-crud-operations-using-cx_oracle/
+# The following drops the tables created for the tutorial
+
+drop table CX_PETS
+/
+
+drop table CX_PEOPLE
+/