Move Primary not defined err to client pkg

Will be used from the graphql package too shortly

client/errors.go

@@ -31,6 +31,7 @@ const (
 	errFailedToUnmarshalCollection         string = "failed to unmarshal collection json"
 	errOperationNotPermittedOnNamelessCols string = "operation not permitted on nameless collection"
 	errInvalidJSONPayload                  string = "invalid JSON payload"
+	errPrimarySideNotDefined               string = "primary side of relation not defined"
 )
 
 // Errors returnable from this package.
@@ -51,6 +52,7 @@ var (
 	ErrMalformedDocID                      = errors.New("malformed document ID, missing either version or cid")
 	ErrInvalidDocIDVersion                 = errors.New("invalid document ID version")
 	ErrInvalidJSONPayload                  = errors.New(errInvalidJSONPayload)
+	ErrPrimarySideNotDefined               = errors.New(errPrimarySideNotDefined)
 )
 
 // NewErrFieldNotExist returns an error indicating that the given field does not exist.
@@ -155,3 +157,10 @@ func NewErrCRDTKindMismatch(cType, kind string) error {
 func NewErrInvalidJSONPaylaod(payload string) error {
 	return errors.New(errInvalidJSONPayload, errors.NewKV("Payload", payload))
 }
+
+func NewErrPrimarySideNotDefined(relationName string) error {
+	return errors.New(
+		errPrimarySideNotDefined,
+		errors.NewKV("RelationName", relationName),
+	)
+}

db/collection.go

@@ -484,7 +484,7 @@ func validateUpdateSchemaFields(
 			}
 
 			if !(proposedField.IsPrimaryRelation || relatedField.IsPrimaryRelation) {
-				return false, NewErrPrimarySideNotDefined(proposedField.RelationName)
+				return false, client.NewErrPrimarySideNotDefined(proposedField.RelationName)
 			}
 
 			if proposedField.IsPrimaryRelation && relatedField.IsPrimaryRelation {

db/errors.go

@@ -31,7 +31,6 @@ const (
 	errRelationalFieldInvalidRelationType       string = "invalid RelationType"
 	errRelationalFieldMissingIDField            string = "missing id field for relation object field"
 	errRelationalFieldMissingRelationName       string = "missing relation name"
-	errPrimarySideNotDefined                    string = "primary side of relation not defined"
 	errPrimarySideOnMany                        string = "cannot set the many side of a relation as primary"
 	errBothSidesPrimary                         string = "both sides of a relation cannot be primary"
 	errRelatedFieldKindMismatch                 string = "invalid Kind of the related field"
@@ -273,13 +272,6 @@ func NewErrRelationalFieldMissingRelationName(name string) error {
 	)
 }
 
-func NewErrPrimarySideNotDefined(relationName string) error {
-	return errors.New(
-		errPrimarySideNotDefined,
-		errors.NewKV("RelationName", relationName),
-	)
-}
-
 func NewErrPrimarySideOnMany(name string) error {
 	return errors.New(
 		errPrimarySideOnMany,