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)
ans=3×1 table
march
_____
981
1414
890
Calculate the sum of the March sales. Assign the result to the MATLAB workspace variable total
and display the result.
total = sum(data.march)
total = 14606
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
ans = "on"
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)
data=1×2 table
month salestotal
_______ __________
"march" 14606
Close Database Connection
close(conn)
See Also
postgresql
| close
| sqlread
| sqlwrite