Update SQL schemas

db/utils.go

@@ -13,6 +13,7 @@ import (
 // InitMeddler registers tags to be used to read/write from SQL DBs using meddler
 func InitMeddler() {
 	meddler.Register("bigint", BigIntMeddler{})
+	meddler.Register("bigintnull", BigIntNullMeddler{})
 }
 
 // BulkInsert performs a bulk insert with a single statement into the specified table.  Example:
@@ -76,3 +77,42 @@ func (b BigIntMeddler) PreWrite(fieldPtr interface{}) (saveValue interface{}, er
 
 	return str, nil
 }
+
+// BigIntNullMeddler encodes or decodes the field value to or from JSON
+type BigIntNullMeddler struct{}
+
+// PreRead is called before a Scan operation for fields that have the BigIntNullMeddler
+func (b BigIntNullMeddler) PreRead(fieldAddr interface{}) (scanTarget interface{}, err error) {
+	return &fieldAddr, nil
+}
+
+// PostRead is called after a Scan operation for fields that have the BigIntNullMeddler
+func (b BigIntNullMeddler) PostRead(fieldPtr, scanTarget interface{}) error {
+	sv := reflect.ValueOf(scanTarget)
+	if sv.Elem().IsNil() {
+		// null column, so set target to be zero value
+		fv := reflect.ValueOf(fieldPtr)
+		fv.Elem().Set(reflect.Zero(fv.Elem().Type()))
+		return nil
+	}
+	// not null
+	encoded := new([]byte)
+	refEnc := reflect.ValueOf(encoded)
+	refEnc.Elem().Set(sv.Elem().Elem())
+	data, err := base64.StdEncoding.DecodeString(string(*encoded))
+	if err != nil {
+		return fmt.Errorf("big.Int decode error: %v", err)
+	}
+	field := fieldPtr.(**big.Int)
+	*field = new(big.Int).SetBytes(data)
+	return nil
+}
+
+// PreWrite is called before an Insert or Update operation for fields that have the BigIntNullMeddler
+func (b BigIntNullMeddler) PreWrite(fieldPtr interface{}) (saveValue interface{}, err error) {
+	field := fieldPtr.(*big.Int)
+	if field == nil {
+		return nil, nil
+	}
+	return base64.StdEncoding.EncodeToString(field.Bytes()), nil
+}