Message type: E = Error
Message class:  SDDIC_DDLA_ANNOCHECK - Messages for annotation usage check 
Message number: 021
Message text: Boolean annotation value must be lowercase
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The SAP error message SDDIC_DDLA_ANNOCHECK021 indicates that there is an issue with the format of a Boolean annotation value in your data model or service definition. Specifically, the error states that the Boolean annotation value must be in lowercase. This is a common requirement in many programming and data definition contexts, where Boolean values are expected to be represented as true or false rather than True or False.
Cause: The error is typically caused by one of the following: Incorrect Case: The Boolean value is defined or used with an uppercase letter (e.g., True or False). Data Model Definition: The data model or service definition may have annotations that are not adhering to the expected lowercase format for Boolean values. Code Generation: If the code is generated from a model, the generation process may have introduced the incorrect casing.
Solution: To resolve this error, you can take the following steps: Check Annotations: Review the annotations in your data
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