Application Development Overview

Continuous Query Language (CQL) is a query language used for data streams. Compared with standard SQL, CQL introduces the concept of window. Data is stored in memory so that in-memory computing can be quickly implemented. CQL query results are computing results at a specific moment of data streams.

CQL has the following features:

• Simple usage: Similar to standard SQL syntax, CQL syntax supports SQL-based quick development.
• Rich functions: Except various standard basic SQL expressions, CQL provides window, pre-window filtering, post-window filtering, and concurrency setting functions for stream processing scenarios to meet requirements in multiple real-time service processing scenarios.
• Easy to scale: CQL provides an extension interface to supporting increasingly complex service scenarios. Users can customize the input, output, serialization, and deserialization to meet specific service requirements.
• Easy to debug: CQL provides detailed explanation of error codes, facilitating users to rectify faults.