Blob conversion function in Cassandra

In Cassandra, Blob data type represents constant hexadecimal data type and the number is defined as 0[xX](hex)+ where hex means hexadecimal. It is useful to store a short string or small images.

In this article we will discuss Blob conversion function which converts the native types into binary data (blob):

typeAsBlob(value)
blobAsType(value) 

Let’s understand with an example.

To create table function_test1 used the following CQL query.

CREATE TABLE function_test1 ( 
Name varchar PRIMARY KEY, 
type_value blob
 ); 

To insert data into the table using the following CQL query.

INSERT INTO function_test1 (Name, type_value) 
       VALUES ('Ashish', bigintAsBlob(5));
INSERT INTO function_test1 (Name, type_value) 
       VALUES ('Rana', bigintAsBlob(9));  

To read the data using the following CQL query.

SELECT * 
FROM function_test1; 

Output:

Now, to convert blobAsBigint then first update the table by using the following CQL query.

ALTER TABLE function_test1 ADD Id bigint; 

Now, again insert data into the updated table. So, let’s have a look.

INSERT INTO function_test1 (Name, Id) 
       VALUES ('Ashish', blobAsBigint(0x0000000000000005));
INSERT INTO function_test1 (Name, Id) 
       VALUES ('Rana', blobAsBigint(0x0000000000000009)); 

To see the final output used the following CQL query.

SELECT * 
FROM function_test1; 

Output: