Glossary

This document is a reference of commonly used terms and definitions.

Dictionary Model

Lectern provides a "meta-schema" which describes a syntax for creating Data Dictionaries. This meta-schema is a set of rules for a JSON document, and any JSON document that correctly applies these rules represents a valid Lectern Dictionary. The meta-schema is defined through code rules in the @overture-stack/lectern-dictionary package.

A JSON-schema version of this meta-schema has been generated and is included in this code base.

This section describes at a high level the component parts of a Lectern Dictionary and the terms used when discussing those parts. The terms defined here are used throughout the documentation and the type system of the Lectern codebase. If you are writing a Lectern Dictionary, you may instead be looking for the reference documentation for Lectern Dictionaries.

Dictionary

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Schema

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Field

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Data Type

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Restrictions

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Schema Restriction

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Field Restriction

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Conditional Field Restriction

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Meta

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Common Types

DataRecord and UnprocessedDataRecord

The DataRecord type represents a single record from some Schema. They are objects with keys that match the fields from a schema and a value that should be one of the valid Lectern data types. There is no guarantee that a DataRecord is "valid", it could have values that fail some restrictions from the schema.

An UnprocessedDataRecord is very similar, but all values are raw string values. These represent a single record as it would be submitted in a test file, for example all the data from a single line in a TSV. These string values will need to be parsed to be converted to their proper types as defined in a schema.

TestResult

Reference: validation/src/types/testResult.ts

A TestResult represents the outcome of a validation test applied to an object. For example, a Field will be validated based on its Restrictions and this will generate a TestResult that will contain a list of ValidationTestErrors if the field is found to be invalid for one or more reasons.

The TestResult object indicates if the object tested was valid or invalid (valid: true) for the given test. When the value is invalid, additional information should be included in the result that describes the conditions that the test failed.

Example Valid TestResult:

{
  valid: true;
}

Example Invalid TestResult, for a field validation that failed due to CodeList restriction:

{
	valid: false,
	details: {
		reason: "INVALID_BY_RESTRICTION",
		value: "Atari",
		errors: [
			{
				type: "codeList",
				rule: ["Nintendo", "Sega", "PlayStation", "Xbox"]
			}
		]
	}
}

Data Processing Verbs

Parsing

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Validating

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Processing

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