%% Insert Data into Database Table Using PostgreSQL Native Interface
% This example shows how to import data from a database into MATLAB®, perform calculations on the data, and export the results to a database table.
% The example assumes that you are connecting to a PostgreSQL database that contains tables named salesvolume and yearlysales. The salesvolume table contains the column names for each month. The yearlysales table contains the column names month and salestotal. Also, the example uses a PostgreSQL database version 9.405 database and the libpq driver version 10.12.
%% Create Database Connection
% Create a PostgreSQL native interface database connection to a PostgreSQL database using the data source name, user name, and password.

datasource = "PostgreSQLDataSource";
username = "dbdev";
password = "matlab";
conn = postgresql(datasource,username,password);

%% Calculate Sum of Sales Volume for One Month
% Import sales volume data for the month of March using the database connection. The salesvolume database table contains sales volume data.

tablename = "salesvolume"; 
data = sqlread(conn,tablename); 

% Display the first three rows of sales volume data. The fourth variable contains the data for the month of March.

head(data(:,4),3) 

% Calculate the sum of the March sales. Assign the result to the MATLAB workspace variable total and display the result.

total = sum(data.march) 

%% Insert Total Sales for One Month into Database
% Retrieve the name of the month from the sales volume data.

month = data.Properties.VariableNames(4);

% Define the names of the columns for the data to insert as a string array.

colnames = ["month" "salestotal"]; 

% Create a MATLAB table that stores the data to export.

results = table(month,total,'VariableNames',colnames); 

% Determine the status of the AutoCommit database flag. This status determines whether or not the insert action can be undone.

conn.AutoCommit 

% The AutoCommit flag is set to on. The database commits the exported data automatically to the database, and this action cannot be undone.
% Insert the sum of sales for the month of March into the yearlysales table.

tablename = "yearlysales"; 
sqlwrite(conn,tablename,results) 

% Import the data from the yearlysales table. This data contains the calculated result.

data = sqlread(conn,tablename) 

%% Close Database Connection

close(conn)

% Copyright 2020 The MathWorks, Inc.