Querying the database

Direct queries

Very often, a single database query is needed to prepare a response to the user. For such simple cases, the JDBCClient provides rxQueryXXX and rxUpdateXXX methods:

String query = sqlQueries.get(SqlQuery.GET_PAGE_BY_ID);
JsonArray params = new JsonArray().add(id);
Single<ResultSet> resultSet = dbClient.rxQueryWithParams(query, params);

Working with a database connection

When direct queries do not fit (e.g. when creating then querying a temporary table), you can generate a reactive flow from a single SQLConnection:

SQLClientHelper.usingConnectionSingle(this.dbClient, conn -> conn (1)
  .rxExecute(sqlQueries.get(SqlQuery.CREATE_PAGES_TABLE)) (2)
  .andThen(Single.just(this)))

1. borrows a connection from the pool and provides it in a callback.

2. returns a Single generated from execution of queries and transformation of results.

You may execute any number of queries and transform results with RxJava operators.