This example shows how to delete data from a database using MATLAB®. Create the SQL statement using deletion SQL syntax; consult your database documentation for the correct syntax. Execute the delete operation on your database using the execute
function with the SQL statement. This example demonstrates deleting records from a PostgreSQL database.
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);
The SQL query sqlquery
selects all rows of data in the table inventorytable
. Execute this SQL query using the database connection. Import the data from the executed query using the fetch
function, and display the last few rows.
sqlquery = "SELECT * FROM inventorytable";
data = fetch(conn,sqlquery);
tail(data,3)
ans=3×4 table
productnumber quantity price inventorydate
_____________ ________ _____ _____________________
11 567 0 "2012-09-11 00:30:24"
12 1278 0 "2010-10-29 18:17:47"
13 1700 14.5 "2009-05-24 10:58:59"
Delete the record for the product number 13
from the table inventorytable
. Specify the product number using the WHERE
clause in the SQL statement sqlquery
.
sqlquery = "DELETE FROM inventorytable WHERE productnumber = 13";
execute(conn,sqlquery)
Display the data in the table inventorytable
after the deletion. The record with product number 13
is missing.
sqlquery = "SELECT * FROM inventorytable";
data = fetch(conn,sqlquery);
tail(data,3)
ans=3×4 table
productnumber quantity price inventorydate
_____________ ________ _____ _____________________
10 723 24 "2012-03-14 13:13:09"
11 567 0 "2012-09-11 00:30:24"
12 1278 0 "2010-10-29 18:17:47"
close(conn)
close
| execute
| fetch
| postgresql