lib/query-tree-builder.js
function getKeyColumn(propDesc, keyPropContainer) {
	if (propDesc.keyColumn)
		return propDesc.keyColumn;
	const keyPropDesc = keyPropContainer.getPropertyDesc(
		propDesc.keyPropertyName);
	return keyPropDesc.column;
}
function getKeyColumn(propDesc, keyPropContainer) {
	if (propDesc.keyColumn)
		return propDesc.keyColumn;
	const keyPropDesc = keyPropContainer.getPropertyDesc(
		propDesc.keyPropertyName);
	return keyPropDesc.column;
}
function getKeyColumn ( propDesc , keyPropContainer ) { if ( propDesc . keyColumn ) return propDesc . keyColumn ; const keyPropDesc = keyPropContainer . getPropertyDesc ( propDesc . keyPropertyName ) ; return keyPropDesc . column ; }
Get map key column.

@private
@param {module:x2node-records~PropertyDescriptor} propDesc Map property
descriptor.
@param {module:x2node-records~PropertiesContainer} keyPropContainer Container
where to look for the key property, if applicable.
@returns {string} Column name.
Get map key column .