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close

Close PostgreSQL native interface database connection

Description

example

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

Examples

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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

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

Introduced in R2020b