shillelagh/src/main/java/shillelagh/QueryBuilder.java
private Object valueOf(String columnName, Object value) {
    java.lang.reflect.Field field;
    try {
      field = tableObject.getDeclaredField(columnName);
    } catch (NoSuchFieldException e) {
      throw new RuntimeException(
          String.format("%s isEqualTo not a field found in %s", columnName, tableObject));
    }
    return field.getType() == String.class ? String.format("\'%s\'", value) : value;
  }
private Object valueOf(String columnName, Object value) {
    java.lang.reflect.Field field;
    try {
      field = tableObject.getDeclaredField(columnName);
    } catch (NoSuchFieldException e) {
      throw new RuntimeException(
          String.format("%s isEqualTo not a field found in %s", columnName, tableObject));
    }
    return field.getType() == String.class ? String.format("\'%s\'", value) : value;
  }
Forces the value to be wrapped with ' if it isEqualTo for a string field.