ycql

name	ycql
description	Use when writing or reviewing CQL code, schema definitions, or application code that targets YugabyteDB's Cassandra-compatible YCQL API (port 9042). Triggers on YCQL tables, partition keys, TTL, batching, or any mention of YugabyteDB with Cassandra/CQL.

YugabyteDB YCQL Best Practices

YCQL is YugabyteDB's Cassandra-compatible API (port 9042). It provides global secondary indexes with strong consistency (ACID) — a key advantage over Apache Cassandra.

Schema Design

Partition Keys and Clustering Columns

Design partition keys for even data distribution and clustering columns for efficient range scans within a partition:

CREATE TABLE orders (
    customer_id UUID,
    order_date TIMESTAMP,
    order_id UUID,
    total DECIMAL,
    PRIMARY KEY ((customer_id), order_date DESC, order_id)
) WITH CLUSTERING ORDER BY (order_date DESC, order_id ASC);

• Partition key (customer_id): Determines tablet placement. Choose for even distribution.
• Clustering columns (order_date, order_id): Determine sort order within a partition.

Global Secondary Indexes

YCQL secondary indexes in YugabyteDB are global and strongly consistent (ACID), unlike Cassandra's local indexes:

CREATE INDEX idx_orders_date ON orders (order_date);

Covering Indexes

Use the clause to serve queries directly from the index without a table lookup: