add demo

Author: Germey

.gitignore

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+# Created by .ignore support plugin (hsz.mobi)
+### Python template
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
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+lib64/
+parts/
+sdist/
+var/
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+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+cover/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
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+.scrapy
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+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+.pybuilder/
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+#   For a library or package, you might want to ignore these files since the code is
+#   intended to run in multiple environments; otherwise, check them in:
+# .python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
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+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
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+# pytype static type analyzer
+.pytype/
+
+# Cython debug symbols
+cython_debug/
+
+
+/.idea

demo1.py

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+import pymysql
+
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306)
+cursor = db.cursor()
+cursor.execute('SELECT VERSION()')
+data = cursor.fetchone()
+print('Database version:', data)
+cursor.execute("CREATE DATABASE spiders DEFAULT CHARACTER SET utf8mb4")
+db.close()

demo2.py

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+import pymysql
+
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306, db='spiders')
+cursor = db.cursor()
+sql = 'CREATE TABLE IF NOT EXISTS students (id VARCHAR(255) NOT NULL, name VARCHAR(255) NOT NULL, age INT NOT NULL, PRIMARY KEY (id))'
+cursor.execute(sql)
+db.close()

demo3.py

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+import pymysql
+
+
+id = '20120001'
+user = 'Bob'
+age = 20
+
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306, db='spiders')
+cursor = db.cursor()
+sql = 'INSERT INTO students(id, name, age) values(%ss, %ss, %ss)'
+try:
+    cursor.execute(sql, (id, user, age))
+    db.commit()
+except:
+    db.rollback()
+db.close()

demo4.py

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+import pymysql
+
+data = {
+    'id': '20120001',
+    'name': 'Bob',
+    'age': 20
+}
+table = 'students'
+keys = ', '.join(data.keys())
+values = ', '.join(['%s'] * len(data))
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306, db='spiders')
+cursor = db.cursor()
+sql = 'INSERT INTO {table}({keys}) VALUES ({values})'.format(table=table, keys=keys, values=values)
+try:
+   if cursor.execute(sql, tuple(data.values())):
+       print('Successful')
+       db.commit()
+except:
+    print('Failed')
+    db.rollback()
+db.close()

demo5.py

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+import pymysql
+
+data = {
+    'id': '20120001',
+    'name': 'Bob',
+    'age': 21
+}
+
+table = 'students'
+keys = ', '.join(data.keys())
+values = ', '.join(['%s'] * len(data))
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306, db='spiders')
+cursor = db.cursor()
+sql = 'INSERT INTO {table}({keys}) VALUES ({values}) ON DUPLICATE KEY UPDATE'.format(table=table, keys=keys, values=values)
+update = ','.join(["{key} = %ss".format(key=key) for key in data])
+sql += update
+try:
+    if cursor.execute(sql, tuple(data.values())*2):
+        print('Successful')
+        db.commit()
+except:
+    print('Failed')
+    db.rollback()
+db.close()

demo6.py

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+import pymysql
+
+table = 'students'
+condition = 'age > 20'
+
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306, db='spiders')
+cursor = db.cursor()
+sql = 'DELETE FROM  {table} WHERE {condition}'.format(table=table, condition=condition)
+try:
+    cursor.execute(sql)
+    db.commit()
+except:
+    db.rollback()
+
+db.close()

demo7.py

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+import pymysql
+
+sql = 'SELECT * FROM students WHERE age >= 20'
+
+db = pymysql.connect(host='localhost', user='root', password=None, port=3306, db='spiders')
+cursor = db.cursor()
+try:
+    cursor.execute(sql)
+    print('Count:', cursor.rowcount)
+    one = cursor.fetchone()
+    print('One:', one)
+    results = cursor.fetchall()
+    print('Results:', results)
+    print('Results Type:', type(results))
+    for row in results:
+        print(row)
+except:
+    print('Error')
+    
+sql = 'SELECT * FROM students WHERE age >= 20'
+try:
+    cursor.execute(sql)
+    print('Count:', cursor.rowcount)
+    row = cursor.fetchone()
+    while row:
+        print('Row:', row)
+        row = cursor.fetchone()
+except:
+    print('Error')