add ConvertAsIndexType

internal/database/constraint.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/chaisql/chai/internal/encoding"
 	"github.com/chaisql/chai/internal/object"
 	"github.com/chaisql/chai/internal/stringutil"
 	"github.com/chaisql/chai/internal/tree"
@@ -158,18 +159,8 @@ func (f FieldConstraints) convertScalarAtPath(path object.Path, v types.Value, c
 	}
 
 	// no constraint have been found for this path.
-	// check if this is an integer and convert it to double.
-	if v.Type() == types.TypeInteger {
-		newV, _ := object.CastAsDouble(v)
-		return newV, nil
-	}
-
-	if v.Type() == types.TypeTimestamp {
-		newV, _ := object.CastAsText(v)
-		return newV, nil
-	}
-
-	return v, nil
+	// convert the value to the type that is stored in the index.
+	return encoding.ConvertAsIndexType(v, types.TypeAny)
 }
 
 func (f FieldConstraints) GetFieldConstraintForPath(path object.Path) *FieldConstraint {

internal/database/iteration.go

@@ -3,6 +3,7 @@ package database
 import (
 	"math"
 
+	"github.com/chaisql/chai/internal/encoding"
 	"github.com/chaisql/chai/internal/object"
 	"github.com/chaisql/chai/internal/tree"
 	"github.com/chaisql/chai/internal/types"
@@ -65,10 +66,6 @@ func (r *Range) Convert(constraints *FieldConstraints, v types.Value, p object.P
 	// is lossless.
 	// if a timestamp is encountered, ensure the field constraint is also a timestamp, otherwise convert it to text.
 	v, err := constraints.ConvertValueAtPath(p, v, func(v types.Value, path object.Path, targetType types.Type) (types.Value, error) {
-		if v.Type() == types.TypeInteger && targetType == types.TypeDouble {
-			return object.CastAsDouble(v)
-		}
-
 		if v.Type() == types.TypeDouble && targetType == types.TypeInteger {
 			f := types.AsFloat64(v)
 			if float64(int64(f)) == f {
@@ -102,10 +99,8 @@ func (r *Range) Convert(constraints *FieldConstraints, v types.Value, p object.P
 				// and thus have to set exclusive to false.
 				r.Exclusive = r.Min == nil || len(r.Min) == 0
 			}
-		}
-
-		if v.Type() == types.TypeTimestamp && targetType == types.TypeText {
-			return object.CastAsText(v)
+		} else {
+			return encoding.ConvertAsIndexType(v, targetType)
 		}
 
 		return v, nil

internal/encoding/conversion.go

@@ -43,8 +43,6 @@ func convertIntegerFromStore(src types.Value, target types.Type) (types.Value, e
 // ConvertAsStoreType converts the value to the type that is stored in the store
 // when there is no constraint on the column.
 func ConvertAsStoreType(src types.Value) (types.Value, error) {
-	// integers are stored as the smallest integer type that can hold the value
-	// even though they are read as doubles.
 	switch src.Type() {
 	case types.TypeTimestamp:
 		// without a type constraint, timestamp values must
@@ -54,3 +52,24 @@ func ConvertAsStoreType(src types.Value) (types.Value, error) {
 
 	return src, nil
 }
+
+// ConvertAsIndexType converts the value to the type that is stored in the index
+// as a key.
+func ConvertAsIndexType(src types.Value, target types.Type) (types.Value, error) {
+	switch src.Type() {
+	case types.TypeInteger:
+		if target == types.TypeAny || target == types.TypeDouble {
+			return object.CastAsDouble(src)
+		}
+		return src, nil
+	case types.TypeTimestamp:
+		// without a type constraint, timestamp values must
+		// always be stored as text to avoid mixed representations.
+		if target == types.TypeAny {
+			return object.CastAsText(src)
+		}
+		return src, nil
+	}
+
+	return src, nil
+}