Function normalizeRelation

drizzle-orm/src/relations.ts:559–634

(
	schema: TablesRelationalConfig,
	tableNamesMap: Record<string, string>,
	relation: Relation,
)

}

export function normalizeRelation(
	schema: TablesRelationalConfig,
	tableNamesMap: Record<string, string>,
	relation: Relation,
): NormalizedRelation {
	if (is(relation, One) && relation.config) {
		return {
			fields: relation.config.fields,
			references: relation.config.references,
		};
	}

	const referencedTableTsName = tableNamesMap[getTableUniqueName(relation.referencedTable)];
	if (!referencedTableTsName) {
		throw new Error(
			`Table "${relation.referencedTable[Table.Symbol.Name]}" not found in schema`,
		);
	}

	const referencedTableConfig = schema[referencedTableTsName];
	if (!referencedTableConfig) {
		throw new Error(`Table "${referencedTableTsName}" not found in schema`);
	}

	const sourceTable = relation.sourceTable;
	const sourceTableTsName = tableNamesMap[getTableUniqueName(sourceTable)];
	if (!sourceTableTsName) {
		throw new Error(
			`Table "${sourceTable[Table.Symbol.Name]}" not found in schema`,
		);
	}

	const reverseRelations: Relation[] = [];
	for (
		const referencedTableRelation of Object.values(
			referencedTableConfig.relations,
		)
	) {
		if (
			(relation.relationName
				&& relation !== referencedTableRelation
				&& referencedTableRelation.relationName === relation.relationName)
			|| (!relation.relationName
				&& referencedTableRelation.referencedTable === relation.sourceTable)
		) {
			reverseRelations.push(referencedTableRelation);
		}
	}

	if (reverseRelations.length > 1) {
		throw relation.relationName
			? new Error(
				`There are multiple relations with name "${relation.relationName}" in table "${referencedTableTsName}"`,
			)
			: new Error(
				`There are multiple relations between "${referencedTableTsName}" and "${
					relation.sourceTable[Table.Symbol.Name]
				}". Please specify relation name`,