diff --git a/loaders/libloader.go b/loaders/libloader.go
index db991cde6..36f1e3741 100644
--- a/loaders/libloader.go
+++ b/loaders/libloader.go
@@ -62,10 +62,16 @@ func (ld LoaderData) UpdateFromCSV(fileName string, record []string,
 		}
 		switch cfgFld.Type {
 		case utils.META_COMPOSED:
-			if valOrig, canCast := ld[cfgFld.FieldId].(string); canCast {
+			if _, has := ld[cfgFld.FieldId]; !has {
+				ld[cfgFld.FieldId] = valStr
+			} else if valOrig, canCast := ld[cfgFld.FieldId].(string); canCast {
 				valOrig += valStr
 				ld[cfgFld.FieldId] = valOrig
 			}
+		case utils.MetaString:
+			if _, has := ld[cfgFld.FieldId]; !has {
+				ld[cfgFld.FieldId] = valStr
+			}
 		}
 	}
 	return
diff --git a/loaders/libloader_test.go b/loaders/libloader_test.go
new file mode 100644
index 000000000..aaabc28dd
--- /dev/null
+++ b/loaders/libloader_test.go
@@ -0,0 +1,178 @@
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package loaders
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/cgrates/cgrates/config"
+	"github.com/cgrates/cgrates/utils"
+)
+
+func TestDataUpdateFromCSVOneFile(t *testing.T) {
+	attrSFlds := []*config.CfgCdrField{
+		&config.CfgCdrField{Tag: "TenantID",
+			FieldId:   "Tenant",
+			Type:      utils.META_COMPOSED,
+			Value:     utils.ParseRSRFieldsMustCompile("0", utils.INFIELD_SEP),
+			Mandatory: true},
+		&config.CfgCdrField{Tag: "ProfileID",
+			FieldId:   "ID",
+			Type:      utils.META_COMPOSED,
+			Value:     utils.ParseRSRFieldsMustCompile("1", utils.INFIELD_SEP),
+			Mandatory: true},
+		&config.CfgCdrField{Tag: "Contexts",
+			FieldId: "Contexts",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("2", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "FilterIDs",
+			FieldId: "FilterIDs",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("3", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "ActivationInterval",
+			FieldId: "ActivationInterval",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("4", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "FieldName",
+			FieldId: "FieldName",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("5", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Initial",
+			FieldId: "Initial",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("6", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Substitute",
+			FieldId: "Substitute",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("7", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Append",
+			FieldId: "Append",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("8", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Weight",
+			FieldId: "Weight",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("9", utils.INFIELD_SEP)},
+	}
+
+	rows := [][]string{
+		[]string{"cgrates.org", "ATTR_1", "*sessions;*cdrs", "*string:Account:1007", "2014-01-14T00:00:00Z", "Account", "*any", "1001", "false", "10"},
+		[]string{"cgrates.org", "ATTR_1", "", "", "", "Subject", "*any", "1001", "true", ""},
+	}
+	lData := make(LoaderData)
+	if err := lData.UpdateFromCSV("Attributes.csv", rows[0], attrSFlds); err != nil {
+		t.Error(err)
+	}
+	eLData := LoaderData{"Tenant": "cgrates.org",
+		"ID":                 "ATTR_1",
+		"Contexts":           "*sessions;*cdrs",
+		"FilterIDs":          "*string:Account:1007",
+		"ActivationInterval": "2014-01-14T00:00:00Z",
+		"FieldName":          "Account",
+		"Initial":            "*any",
+		"Substitute":         "1001",
+		"Append":             "false",
+		"Weight":             "10",
+	}
+	if !reflect.DeepEqual(eLData, lData) {
+		t.Errorf("expecting: %+v, received: %+v", eLData, lData)
+	}
+	lData = make(LoaderData)
+	if err := lData.UpdateFromCSV("Attributes.csv", rows[1], attrSFlds); err != nil {
+		t.Error(err)
+	}
+	eLData = LoaderData{"Tenant": "cgrates.org",
+		"ID":                 "ATTR_1",
+		"Contexts":           "",
+		"FilterIDs":          "",
+		"ActivationInterval": "",
+		"FieldName":          "Subject",
+		"Initial":            "*any",
+		"Substitute":         "1001",
+		"Append":             "true",
+		"Weight":             "",
+	}
+	if !reflect.DeepEqual(eLData, lData) {
+		t.Errorf("expecting: %+v, received: %+v", eLData, lData)
+	}
+}
+
+func TestDataUpdateFromCSVMultiFiles(t *testing.T) {
+	attrSFlds := []*config.CfgCdrField{
+		&config.CfgCdrField{Tag: "TenantID",
+			FieldId:   "Tenant",
+			Type:      utils.MetaString,
+			Value:     utils.ParseRSRFieldsMustCompile("^cgrates.org", utils.INFIELD_SEP),
+			Mandatory: true},
+		&config.CfgCdrField{Tag: "ProfileID",
+			FieldId:   "ID",
+			Type:      utils.META_COMPOSED,
+			Value:     utils.ParseRSRFieldsMustCompile("File2.csv:1", utils.INFIELD_SEP),
+			Mandatory: true},
+		&config.CfgCdrField{Tag: "Contexts",
+			FieldId: "Contexts",
+			Type:    utils.MetaString,
+			Value:   utils.ParseRSRFieldsMustCompile("^*any", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "FieldName",
+			FieldId: "FieldName",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("File1.csv:5", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Initial",
+			FieldId: "Initial",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("File1.csv:6", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Substitute",
+			FieldId: "Substitute",
+			Type:    utils.META_COMPOSED,
+			Value:   utils.ParseRSRFieldsMustCompile("File1.csv:7", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Append",
+			FieldId: "Append",
+			Type:    utils.MetaString,
+			Value:   utils.ParseRSRFieldsMustCompile("^true", utils.INFIELD_SEP)},
+		&config.CfgCdrField{Tag: "Weight",
+			FieldId: "Weight",
+			Type:    utils.MetaString,
+			Value:   utils.ParseRSRFieldsMustCompile("^10", utils.INFIELD_SEP)},
+	}
+
+	loadRun1 := map[string][]string{
+		"File1.csv": []string{"ignored", "ignored", "ignored", "ignored", "ignored", "Subject", "*any", "1001", "ignored", "ignored"},
+		"File2.csv": []string{"ignored", "ATTR_1"},
+	}
+	lData := make(LoaderData)
+	for fName, record := range loadRun1 {
+		if err := lData.UpdateFromCSV(fName, record, attrSFlds); err != nil {
+			t.Error(err)
+		}
+	}
+
+	eLData := LoaderData{"Tenant": "cgrates.org",
+		"ID":         "ATTR_1",
+		"Contexts":   "*any",
+		"FieldName":  "Subject",
+		"Initial":    "*any",
+		"Substitute": "1001",
+		"Append":     "true",
+		"Weight":     "10",
+	}
+	if !reflect.DeepEqual(eLData, lData) {
+		t.Errorf("expecting: %+v, received: %+v", eLData, lData)
+	}
+}
diff --git a/utils/consts.go b/utils/consts.go
index 121fbc957..1f24028a9 100755
--- a/utils/consts.go
+++ b/utils/consts.go
@@ -330,6 +330,7 @@ const (
 	TRIGGER_BALANCE_EXPIRED      = "*balance_expired"
 	HIERARCHY_SEP                = ">"
 	META_COMPOSED                = "*composed"
+	MetaString                   = "*string"
 	NegativePrefix               = "!"
 	MatchStartPrefix             = "^"
 	MatchEndPrefix               = "$"