/// <summary>
/// Reads data from local store by executing the query.
/// </summary>
/// <param name="query">The query to execute on local store.</param>
/// <returns>A task that will return with results when the query finishes.</returns>
public override Task <JToken> ReadAsync(MobileServiceTableQueryDescription query)
{
if (query == null)
{
throw new ArgumentNullException("query");
}
this.EnsureInitialized();
var formatter = new SqlQueryFormatter(query);
string sql = formatter.FormatSelect();
IList <JObject> rows = this.ExecuteQuery(query.TableName, sql, formatter.Parameters);
JToken result = new JArray(rows.ToArray());
if (query.IncludeTotalCount)
{
sql = formatter.FormatSelectCount();
IList <JObject> countRows = this.ExecuteQuery(query.TableName, sql, formatter.Parameters);
long count = countRows[0].Value <long>("count");
result = new JObject()
{
{ "results", result },
{ "count", count }
};
}
return(Task.FromResult(result));
}
/// <summary>
/// Deletes items from local table that match the given query.
/// </summary>
/// <param name="query">A query to find records to delete.</param>
/// <returns>A task that completes when delete query has executed.</returns>
public override Task DeleteAsync(MobileServiceTableQueryDescription query)
{
if (query == null)
{
throw new ArgumentNullException("query");
}
this.EnsureInitialized();
var formatter = new SqlQueryFormatter(query);
string sql = formatter.FormatDelete();
this.ExecuteNonQuery(sql, formatter.Parameters);
return(Task.FromResult(0));
}
public string FormatDelete()
{
var delQuery = this.query.Clone(); // create a copy to avoid modifying the original
delQuery.Selection.Clear();
delQuery.Selection.Add(MobileServiceSystemColumns.Id);
delQuery.IncludeTotalCount = false;
var formatter = new SqlQueryFormatter(delQuery);
string selectIdQuery = formatter.FormatSelect();
string idMemberName = SqlHelpers.FormatMember(MobileServiceSystemColumns.Id);
string tableName = SqlHelpers.FormatTableName(delQuery.TableName);
string command = string.Format("DELETE FROM {0} WHERE {1} IN ({2})", tableName, idMemberName, selectIdQuery);
this.Parameters = formatter.Parameters;
return(command);
}