diff --git a/database/gdb/gdb_model_cache.go b/database/gdb/gdb_model_cache.go
index e05d40740..914f315dc 100644
--- a/database/gdb/gdb_model_cache.go
+++ b/database/gdb/gdb_model_cache.go
@@ -34,9 +34,10 @@ type CacheOption struct {
 	Force bool
 }
 
+// selectCacheItem is the cache item for SELECT statement result.
 type selectCacheItem struct {
-	Result            Result
-	FirstResultColumn string
+	Result            Result // Sql result of SELECT statement.
+	FirstResultColumn string // The first column name of result, for Value/Count functions.
 }
 
 // Cache sets the cache feature for the model. It caches the result of the sql, which means
@@ -128,7 +129,6 @@ func (m *Model) makeSelectCacheKey(sql string, args ...interface{}) string {
 	if len(cacheKey) == 0 {
 		cacheKey = fmt.Sprintf(
 			`GCache@Schema(%s):%s`,
-			m.db.GetSchema(),
 			gmd5.MustEncryptString(sql+", @PARAMS:"+gconv.String(args)),
 		)
 	}
diff --git a/database/gdb/gdb_model_select.go b/database/gdb/gdb_model_select.go
index ebe8432c9..02e8b8be5 100644
--- a/database/gdb/gdb_model_select.go
+++ b/database/gdb/gdb_model_select.go
@@ -176,7 +176,10 @@ func (m *Model) Value(fieldsAndWhere ...interface{}) (Value, error) {
 			return v, nil
 		}
 	}
-	return nil, gerror.NewCode(gcode.CodeInternalError, `query value error`)
+	return nil, gerror.NewCode(
+		gcode.CodeInternalError,
+		`query value error: the internal context data is missing. there's' internal issue should be fixed'`,
+	)
 }
 
 // Array queries and returns data values as slice from database.
@@ -390,7 +393,10 @@ func (m *Model) Count(where ...interface{}) (int, error) {
 				return v.Int(), nil
 			}
 		}
-		return 0, gerror.NewCode(gcode.CodeInternalError, `query count error`)
+		return 0, gerror.NewCode(
+			gcode.CodeInternalError,
+			`query count error: the internal context data is missing. there's' internal issue should be fixed'`,
+		)
 	}
 	return 0, nil
 }