generateUpdateSQL method

FutureOr<SQL> generateUpdateSQL(Transaction transaction, String entityName, String table, Object id, Map<String, Object?> fields,)

Implementation

FutureOr<SQL> generateUpdateSQL(Transaction transaction, String entityName,
    String table, Object id, Map<String, Object?> fields) {
  if (fields.isEmpty) return SQL.dummy;

  var retTableScheme = getTableScheme(table);

  return retTableScheme.resolveMapped((tableScheme) {
    if (tableScheme == null) {
      var errorMsg = "Can't find `TableScheme` for table: $table";
      _log.severe(errorMsg);
      throw StateError(errorMsg);
    }

    var context = EncodingContext(entityName,
        namedParameters: fields, transaction: transaction);

    var idFieldName = tableScheme.idFieldName!;
    var idPlaceholder =
        _conditionSQLGenerator.parameterPlaceholder(idFieldName);

    var fieldsValues =
        tableScheme.getFieldsValues(fields, fields: fields.keys.toSet());

    // No value to update:
    if (fieldsValues.isEmpty) {
      return SQL.dummy;
    }

    var fieldsKeys = fieldsValues.keys.toList();

    var fieldsValuesInSQL = <String, Object?>{idFieldName: id};

    return fieldsKeys
        .map((f) => fieldValueToSQL(
            context, tableScheme, f, fieldsValues[f], fieldsValuesInSQL))
        .toList(growable: false)
        .resolveAll()
        .resolveMapped((values) {
      var q = dialect.elementQuote;
      var sql = StringBuffer();

      sql.write('UPDATE $q');
      sql.write(table);
      sql.write('$q SET ');

      for (var i = 0; i < values.length; ++i) {
        var f = fieldsKeys[i];
        var v = values[i];

        if (i > 0) sql.write(' , ');
        sql.write(q);
        sql.write(f);
        sql.write(q);
        sql.write(' = ');
        sql.write(v);
      }

      if (dialect.acceptsOutputSyntax) {
        sql.write(' OUTPUT INSERTED.');
        sql.write(q);
        sql.write(idFieldName);
        sql.write(q);
      }

      sql.write(' WHERE ');

      var conditionSQL = '$idFieldName = $idPlaceholder';
      sql.write(conditionSQL);

      if (dialect.acceptsReturningSyntax) {
        sql.write(' RETURNING $q$table$q.$q$idFieldName$q');
      }

      return SQL(sql.toString(), null, fields, fieldsValuesInSQL,
          sqlCondition: conditionSQL,
          entityName: table,
          idFieldName: idFieldName,
          mainTable: table);
    });
  });
}