implement IsStringType

Author: angelamayxie

server/types/type.go

@@ -625,12 +625,7 @@ func (t *DoltgresType) MaxCharacterLength() int64 {
 
 // IsNumericType implements the sql.NumberType interface.
 func (t *DoltgresType) IsNumericType() bool {
-	switch t.TypCategory {
-	case TypeCategory_NumericTypes:
-		return true
-	default:
-		return false
-	}
+	return t.TypCategory == TypeCategory_NumericTypes
 }
 
 // IsFloat implements the sql.NumberType interface.
@@ -663,6 +658,11 @@ func (t *DoltgresType) DisplayWidth() int {
 	}
 }
 
+// IsStringType implements the sql.StringType interface.
+func (t *DoltgresType) IsStringType() bool {
+	return t.TypCategory == TypeCategory_StringTypes
+}
+
 // MaxSerializedWidth implements the types.ExtendedType interface.
 func (t *DoltgresType) MaxSerializedWidth() sql.ExtendedTypeSerializedWidth {
 	if t.TypLength < 0 {