update method

@override Future update(Entity entity, Map data, Iterable<String>? fields)

Updates the entity with the given OID into database. *

• • data - the content of the entity. It might contain
• more fields than what are specified in fields.
• And, these fields shall be ignored.
• • fields - the fields to update. If null, all fields in data
• shall be stored.

Implementation

@override
Future update(Entity entity, Map data, Iterable<String>? fields) {
  assert(fields == null || fields is Set
      || fields.toSet().length == fields.length, "Dup? $fields");

  final sql = StringBuffer('update "')
    ..write(entity.otype)..write('" set ');
  final fds = fields == null ? data.keys: fields;

  bool first = true;
  for (final fd in fds) {
    if (fd == fdOtype || fd == fdOid)
      continue;

    if (first) first = false;
    else sql.write(',');
    sql..write('"')..write(fd)..write('"')..write("=@")..write(fd);

    final dbType = entity.getDBType(fd);
    if (dbType?.isNotEmpty ?? false) sql..write(':')..write(dbType);

    if (!data.containsKey(fd)) //postgresql2 driver needs every field
      data[fd] = null;
  }
  if (first)
    return Future.value(); //nothing to update

  sql.write(' where "oid"=@oid');
  data[fdOid] = entity.oid;

  var sqlStatement = sql.toString();
  if (entity is SqlFlavor) {
    final flavor = (entity as SqlFlavor).updateFlavor;
    if (flavor != null) sqlStatement = flavor(sqlStatement, data);
  }

  return access.execute(sqlStatement, data);
}