Welcome
Extending Platform
This section guides developers on customizing and extending Detect solutions. It covers the solution's folder structure, configuration files, integration methods, and provides insights into the Detect Expression Language and its built-in functions.
Detect Expression Language
Null Values

Getting Started
Welcome to the documentation for HCL Detect, where you can find information about how to install, maintain, and use this service.
Installation
Learn more about HCL Detect installation and deploying core components of the product.
Administration
Learn about how to configure, manage, and maintain HCL Detect environments. It includes details on system setup, user management, and permissions, ensuring seamless operation and efficient deployment of your continuous delivery processes.
Working with Platform
The section provides comprehensive instructions for creating, configuring, and managing marketing events. It covers topics such as defining audience conditions, setting up triggers, deploying events, and tracking their performance. Additionally, this section includes explanations of key terminology and offers advanced options to optimize event management.
Extending Platform
This section guides developers on customizing and extending Detect solutions. It covers the solution's folder structure, configuration files, integration methods, and provides insights into the Detect Expression Language and its built-in functions.
- Folder Structure
  This section provides an overview of the basic solution folder structure. It describes the contents of each folder and their purpose.
- drive.json File
  This page explains the structure and purpose of the drive.json file used in HCL Detect. It outlines required configurations including database settings, user profiles, communication parameters, system health metrics, and other operational settings. Proper setup of this file is essential before launching the application.
- Configurations
- Integrations
- Solution Source Code
  This page outlines the structure and components of a solution source in HCL Detect. It details how solutions are packaged, including profiles, feed models, applications, and configurations, enabling deployment and reuse across different environments.
- Detect Expression Language
- Detect Expression Language Built-in Functions
Platform Data Model
This section provides detailed information about the internal tables used within the Detect module. It includes descriptions of each table's structure, purpose, and relationships, aiding administrators and developers in understanding and managing the underlying database schema effectively.
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Null Values

Attributes in HCL Detect Expression Language are nullable, that is, attributes can take null values. To denote a null value, the null keyword is used.

Only the following actions are legal on the expressions with null values:

Built-in function calls: A nullable function parameter can take a null value. E.g.: the second parameter in the list.indicesOf([1, 2, null, 4, 5, null], null) call
Ternary operations: The values returned from choices can be null. E.g.: string.startsWith(profile.areaCode, "AREA_") ? profile.areaCode : null where areaCode is a profile attribute of the String type
List items: Null values can be list items. E.g.: [null, 3, 5, 6, null]
List containment check operations: Null values can be used on the left hand side. E.g.: null not in [null, 3, 5, 6, null]
Equality check operations: Null values can be compared for equality and non-equality. E.g.: MSISDN == null where MSISDN is a tuple attribute (Note: For comparisons with null values, the isNull operator can also be used. Examples: isNull(null) yields trueisNull(profile.x) yields false if the x profile attribute is not null)
Type conversions: The type conversion rules are similar to the ones for non-null expressions. Some examples that are legal: List(Int32)(null), Int32(null), String(Int32(null)), some examples that are illegal: List(Int32)(List(Int64)(null)), Int64(List(Int32)(null)), Bool(Int32(null)), List(Int16)(Double(null))