CCL Project Basics

ESP projects are written in CCL, an SQL-like language which specifies a data flow (by defining streams, windows, operations, and connections), and provides the capability to incorporate functions written in other languages, such as SPLASH, to handle more complex computational work.

Windows
A window is a stateful element that can be named or unnamed, and retains rows based on a defined retention policy.
Delta Streams
Delta streams are stateless elements that can understand all opcodes.
Comparing Streams, Windows, and Delta Streams
Streams, windows, and delta streams offer different characteristics and features, but also share common designation, visibility, and column parameters.
Input/Output/Local
You can designate streams, windows, and delta streams as input, output, or local.
Implicit Columns
All streams, windows, and delta streams use three implicit columns called ROWID, ROWTIME, and BIGROWTIME.
Schemas
A schema defines the structure of data rows in a stream or window.
Stores
Set store defaults, or choose a log store or memory store to specify how data from a window is saved.
CCL Continuous Queries
Build a continuous query using clauses and operators to specify its function. This section provides reference for queries, query clauses, and operators.
Adapters
Adapters connect the Event Stream Processor to the external world.
Order of Elements
Determine the order of CCL project elements based on clause and statement syntax definitions and limitations.