Variables, values and scope in a Flow
Velox resolves values from several scopes. Choose the narrowest suitable scope and document where each value originates; identical display text does not imply identical lifetime or persistence.
| Value source | Scope and lifetime | Typical use |
|---|---|---|
| Definition criteria/parameters | Saved on a Flow data item; processed when the data opens | Database filters and reviewed runtime criteria |
| Flow locals | Current Flow execution; passed into a Sub Action | Intermediate values shared by scripts/steps in one call chain |
| Tags in a property | Evaluated by the consuming step at runtime | File names, command parameters, SQL/report output details |
| General Setup/system values | Environment-wide configuration | Default directories, notification settings and runtime identities |
| Request data | Current REST execution | Request fields mapped through the configured request Definition |
| File/record fields | Current opened data/record | Mapping, reporting and script logic |
Design rules
- Use stable, descriptive names and state the expected type, nullability and format.
- Treat empty, missing, zero and null as different states unless the consumer explicitly equates them.
- Do not store credentials, tokens or private keys in ordinary Flow parameters, locals, script text or command arguments.
- Validate/tag-escape values before they enter SQL, command lines, file paths or remote requests. Runtime substitution is not automatic input sanitisation.
- A Sub Action inherits the parent's test flag and locals. A separately linked successor is a new successful-follow-on execution and must not be assumed to share every transient object.
- Values can be reset when the Flow object is returned to the pool. Do not rely on an in-memory value surviving into a later trigger.
Verification
For each dynamic value, test an ordinary value, empty/missing value, boundary length, delimiter/quote characters, non-ASCII content and an invalid value. Inspect the actual SQL parameter, output file name/content or destination effect using sanitised data. Keep high-detail SQL/HTTP/file logging temporary because it can capture the evaluated values.
Use the installed Help > Code Library for the exact scripting functions available in the local Velox version. See database data items, file data items and REST invocation for their context-specific rules.