title: Update SQL Records Based on Pandas DataFrame
body: <p>I have established connection with SQL using below code and have extracted the data from SQL table, converted into dataframe and ran the predictive model. I have the output generated and want to add the values of output column alone in the database based on Unique ID column.</p>
  <pre><code>server = 'Servername' 
  database = 'DBName' 
  username = 'username' 
  password = 'password' 
  cnxn = pyodbc.connect('DRIVER={SQL Server};SERVER='+server+';DATABASE='+database+';UID='+username+';PWD='+ password)
  
  sql ='SELECT * FROM TableName'
  DF= pd.read_sql(sql,cnxn)
  </code></pre>
  <p>I have columns 'UniqueID','Description','Date','Predicted' in dataframe 'DF' which is retrieved from database. I have predicted the output 'Predicted' and is available in my dataframe. I need to overwrite back only the value in 'Predicted' column of the database based on UniqueID.</p>
  <p>Please let me know if there is any way out or we can just overwrite complete dataframe to database table.</p>