Update Data. To update a counter in a counter table, specify the increment or decrement to the counter column. Upsert means that Cassandra will insert a row if a primary key does not exist already otherwise if primary key already exists, it will update that row. I have a table for my products in Cassandra. In this table I store the product name and seller name (there may be thousands of sellers) and score (Product score of the seller) so as following. ... UPDATE cannot update the values of a row's primary key fields. CREATE TABLE IF NOT EXISTS comments_by_video ( videoid uuid, commentid timeuuid, userid uuid, comment text, PRIMARY KEY ((videoid), commentid) ) WITH CLUSTERING ORDER BY (commentid DESC); So looking at PRIMARY KEY ((videoid), commentid) both videoid and commentid are used to create a unique row. In Cassandra, a table can have a number of rows. Cassandra rejects USING TIMESTAMP or USING TTL … Each row is referenced by a primary key, also called the row key. CQL (Cassandra Query Language) is a query language for the DataStax Enterprise database. Let’s take an example to understand the uuid() function. Primary key columns. The uuid() function is suitable for use in insert or update statements and uuid() function takes no parameter value to generate a unique random Type 4 UUID value which is guaranteed unique value. 1. A PRIMARY KEY consists of a the partition key followed by the clustering columns. The following keywords are used while updating data in a table − Where − This clause is used to select the row to be updated.. Set − Set the value using this keyword.. Must − Includes all the columns composing the primary key.. The partition key columns are the first part of primary key and their role is to spread data evenly around the cluster. ... use the UPDATE command. CREATE TABLE products ( product_name varchar, seller_name varchar, score int, primary key (product_name, seller_name) ); All primary key columns and their values must be specified in the WHERE clause to identify a row. Updating Data in a Table. Cassandra does upsert. In Cassandra 3.0 and earlier, you can only insert values smaller than 64 kB into a clustering column. Figure 4-5 shows how each partition is uniquely identified by a partition key, and how the clustering keys are used to uniquely identify the rows within a partition. Cassandra also supports an additional construct called a static column, which is for storing data that is not part of the primary key but is shared by every row in a partition. CQL (Cassandra Query Language) is a query language for the DataStax Enterprise database. We'll need both to update our record. ... UPDATE cannot update the values of a row's primary key fields. So, let's make our page_name column as a composite primary key with the page_id . 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