close

Close PostgreSQL native interface database connection

Syntax

close(conn)

Description

close(conn) closes and invalidates the PostgreSQL native interface database connection to free up database and driver resources.

Examples

Connect to PostgreSQL Database Using PostgreSQL Native Interface

Create a PostgreSQL native interface connection to a PostgreSQL database. Then, import data from the database into MATLAB® and perform simple data analysis. Close the database connection.

This example assumes that you are connecting to a PostgreSQL database version 9.405 using the libpq driver version 10.12.

Connect to the database using the data source name, user name, and password.

datasource = "PostgreSQLDataSource";
username = "dbdev";
password = "matlab";

conn = postgresql(datasource,username,password)

conn = 
  connection with properties:

                  DataSource: "PostgreSQLDataSource"
                    UserName: "dbdev"

  Database Properties:

                  AutoCommit: "on"
                LoginTimeout: 0
      MaxDatabaseConnections: 100

  Catalog and Schema Information:

              DefaultCatalog: "toystore_doc"
                    Catalogs: "toystore_doc"
                     Schemas: ["pg_toast", "pg_temp_1", "pg_toast_temp_1" ... and 3 more]

  Database and Driver Information:

         DatabaseProductName: "PostgreSQL"
      DatabaseProductVersion: "9.405"
                  DriverName: "libpq"
               DriverVersion: "10.12"

The property sections of the connection object are:

• Database Properties — Information about the database configuration

• Catalog and Schema Information — Names of catalogs and schemas in the database

• Database and Driver Information — Names and versions of the database and driver

Import all data from the table inventoryTable into MATLAB using the sqlread function. Display the first three rows of data.

tablename = "inventoryTable";
data = sqlread(conn,tablename);
head(data,3)

ans=3×4 table
    productnumber    quantity    price        inventorydate    
    _____________    ________    _____    _____________________

          1            1700      14.5     "2014-09-23 09:38:34"
          2            1200         9     "2014-07-08 22:50:45"
          3             356        17     "2014-05-14 07:14:28"

Determine the highest product quantity from the table.

max(data.quantity)

ans = 9000

Close the database connection conn.

close(conn)

Input Arguments

conn — PostgreSQL native interface database connection

connection object

PostgreSQL native interface database connection, specified as a connection object.

Version History

Introduced in R2020b