Updating a List in Cassandra
In Cassandra list is a Collection Data Type. In this article, we will discuss how we can update a list in different ways such that we can add elements in the list at any position where we want. we can also append a list.
Let’s discuss one by one.
Consider cluster1 is a keyspace.
CREATE KEYSPACE cluster1 WITH replication = {'class': 'SimpleStrategy', 'replication_factor' : 1};
Now, here we are going to create a table first. let’s have a look.
Create Table Food_App ( Cafe_id Int Primary Key, Order_Date Date, Order_status Text, Cafe_items list<text> );
Now, we are going to insert some data into the Food_App table.
Let’s have a look.
INSERT INTO Food_App (Cafe_id, Order_Date, Order_status, Cafe_items) VALUES (8045, '2019-02-13', 'Available', {'Banana', 'Mango', 'Apple'}); INSERT INTO Food_App (Cafe_id, Order_Date, Order_status, Cafe_items) VALUES (8046, '2019-02-15', 'Not Available', {'guava', 'juice', 'milk'}); INSERT INTO Food_App (Cafe_id, Order_Date, Order_status, Cafe_items) VALUES (8047, '2019-02-18', 'Available', {'grapes', 'papaya', 'mix fruit'});
Now, let’s see the output.
select * from Food_App;
Output:
Updating a list:
UPDATE Food_App SET Cafe_items = ['fruits', 'lemon tea', 'green tea'] Where Cafe_id = 8045;
Now, let’s see the output.
select * from Food_App;
Output:
To append an element to the list, switch the order of the new element data and the list name:
UPDATE Food_App SET Cafe_items = Cafe_items + ['bread'] WHERE Cafe_id = 8045;
Now, let’s see the output.
select * from Food_App;
Output:
To prepend an element to the list, enclose it in square brackets and use the addition (+) operator:
UPDATE Food_App SET Cafe_items = ['bread']+Cafe_items WHERE Cafe_id = 8046;
Now, let’s see the output.
select * from Food_App;
Output: