public CqlRowSet GetRows()
{
Statement query = new SimpleStatement("SELECT * FROM simplex.songs;");
IAsyncResult asyncResult = Session.BeginExecute(query, null, null);
asyncResult.AsyncWaitHandle.WaitOne();
CqlRowSet result = Session.EndExecute(asyncResult);
return result;
}
/// <summary>
/// Gets the list of temperature stored for a provided weather station and day.
/// </summary>
public RowSet GetTemperatureRecords(string weatherStationId, DateTime day)
{
var selectCql = "SELECT * FROM temperature_by_day WHERE weatherstation_id = ? AND date = ?";
//Create a statement
var selectStatement = new SimpleStatement(selectCql);
//Add the parameters
selectStatement.Bind(weatherStationId, DateTime.Now.ToString("yyyyMMdd"));
//Execute the select statement
return Session.Execute(selectStatement);
}
/// <summary>
/// Add a temperature information for a given weather station
/// </summary>
public void AddTemperature(string weatherStationId, decimal value)
{
var insertCql = @"
INSERT INTO temperature_by_day
(weatherstation_id, date, event_time, temperature)
VALUES
(?, ?, ?, ?)";
//Create an insert statement
var insertStatement = new SimpleStatement(insertCql);
//Bind the parameters to the statement
insertStatement.Bind(weatherStationId, DateTime.Now.ToString("yyyyMMdd"), DateTime.Now, value);
//You can set other options of the statement execution, for example the consistency level.
insertStatement.SetConsistencyLevel(ConsistencyLevel.Quorum);
//Execute the insert
Session.Execute(insertStatement);
}
/// <summary>
/// Add a temperature information for a given weather station asynchronously
/// </summary>
public Task AddTemperatureAsync(string weatherStationId, decimal value)
{
//It is basically the same code as the AddTemperature
//Except it returns a Task that already started but didn't finished
//The row would not be in Cassandra yet when this method finishes executing.
var insertCql = @"
INSERT INTO temperature_by_day
(weatherstation_id, date, event_time, temperature)
VALUES
(?, ?, ?, ?)";
//Create an insert statement
var insertStatement = new SimpleStatement(insertCql);
//Bind the parameters to the statement
insertStatement.Bind(weatherStationId, DateTime.Now.ToString("yyyyMMdd"), DateTime.Now, value);
//You can set other options of the statement execution, for example the consistency level.
insertStatement.SetConsistencyLevel(ConsistencyLevel.Quorum);
//Execute the insert
return Session.ExecuteAsync(insertStatement);
}
public static void Run()
{
// this sample requires buffering
Cluster cluster = Cluster.Builder().AddContactPoint("127.0.0.1").Build();
using (var session = cluster.Connect())
{
const string cqlKeyspaces = "SELECT * from system.schema_keyspaces";
var query = new SimpleStatement(cqlKeyspaces).EnableTracing();
var allTasks = new List<Task>();
for (int i = 0; i < 100; ++i)
{
var futRes = Task<RowSet>.Factory.FromAsync(session.BeginExecute, session.EndExecute, cqlKeyspaces, ConsistencyLevel.Default, null)
.ContinueWith(t => DisplayKeyspace(t.Result));
allTasks.Add(futRes);
}
Task.WaitAll(allTasks.ToArray());
}
cluster.Shutdown();
}
public IAsyncResult GetRowsAsynchronously(String query)
{
Statement statement = new SimpleStatement(query);
return Session.BeginExecute(statement, null, null);
}
private void DoFetchTrace()
{
try
{
var sessionStatement = new SimpleStatement(string.Format(SelectSessionsFormat, _traceId))
.SetConsistencyLevel(ConsistencyLevel.One);
var sessionRow = _session.Execute(sessionStatement).First();
_requestType = sessionRow.GetValue<string>("request");
if (!sessionRow.IsNull("duration"))
{
_duration = sessionRow.GetValue<int>("duration");
}
_coordinator = sessionRow.GetValue<IPAddress>("coordinator");
if (!sessionRow.IsNull("parameters"))
{
_parameters = sessionRow.GetValue<IDictionary<string, string>>("parameters");
}
_startedAt = sessionRow.GetValue<DateTimeOffset>("started_at").ToFileTime();
if (sessionRow.GetColumn("client") != null)
{
ClientAddress = sessionRow.GetValue<IPAddress>("client");
}
_events = new List<Event>();
var eventStatement = new SimpleStatement(string.Format(SelectEventsFormat, _traceId))
.SetConsistencyLevel(ConsistencyLevel.One);
var eventRows = _session.Execute(eventStatement);
foreach (var row in eventRows)
{
_events.Add(new Event(row.GetValue<string>("activity"),
new DateTimeOffset(
Utils.GetTimestampFromGuid(row.GetValue<Guid>("event_id")) +
(new DateTimeOffset(1582, 10, 15, 0, 0, 0, TimeSpan.Zero)).Ticks, TimeSpan.Zero),
row.GetValue<IPAddress>("source"),
row.IsNull("source_elapsed") ? 0 : row.GetValue<int>("source_elapsed"),
row.GetValue<string>("thread")));
}
}
catch (Exception ex)
{
_logger.Error("Unexpected exception while fetching query trace", ex);
throw new TraceRetrievalException("Unexpected exception while fetching query trace", ex);
}
}
public long GetLastStopEvent(Guid videoId, String userName)
{
long videoTimestamp = 0;
// Get a list of the last 5 events to find the last stop
Statement statement = new SimpleStatement(
"SELECT event, video_timestamp FROM videodb.video_event " +
"WHERE videoId = " + videoId + " AND username = "******"LIMIT 5;");
RowSet rows = session.Execute(statement);
foreach (Row row in rows.GetRows())
{
// Find the first stop event, store it and stop the loop
if ( row.GetValue<String>("event").ToLower().Equals("stop") )
{
videoTimestamp = row.GetValue<long>("video_timestamp");
break;
}
}
return videoTimestamp;
}
/// <summary>
/// Gets multiple user profiles by their Ids.
/// </summary>
public async Task<IEnumerable<UserProfile>> GetUserProfiles(ISet<Guid> userIds)
{
if (userIds == null || userIds.Count == 0) return Enumerable.Empty<UserProfile>();
// Since we're essentially doing a multi-get here, limit the number userIds (i.e. partition keys) to 20 in an attempt
// to enforce some performance sanity. Anything larger and we might want to consider a different data model that doesn't
// involve doing a multi-get
if (userIds.Count > 20) throw new ArgumentOutOfRangeException("userIds", "Cannot do multi-get on more than 20 user id keys.");
// As an example, we'll do the multi-get at the CQL level using an IN() clause (i.e. let Cassandra handle it). For an example of
// doing it at the driver level, see the VideoReadModel.GetVideoPreviews method
// Build a parameterized CQL statement with an IN clause
var parameterList = string.Join(", ", Enumerable.Repeat("?", userIds.Count));
var statement =
new SimpleStatement(string.Format("SELECT userid, firstname, lastname, email FROM users WHERE userid IN ({0})", parameterList));
statement.Bind(userIds.Cast<object>().ToArray());
// Execute and map to UserProfile object
RowSet resultRows = await _session.ExecuteAsync(statement).ConfigureAwait(false);
return resultRows.Select(MapRowToUserProfile).ToList();
}
