/// <summary>
/// Gets a query filter that should uniquely identify
/// the current instance. The default implementation
/// compares the Id/key field to the current instance's.
/// </summary>
public override IQueryFilter GetUniqueFilter()
{
if (UniqueFilterProvider != null)
{
return(UniqueFilterProvider(this));
}
else
{
var colFilter = new SonColumns();
return(colFilter.KeyColumn == IdValue);
}
}
/// <summary>
/// Execute a query and return the number of results
/// </summary>
/// <param name="where">A WhereDelegate that recieves a SonColumns
/// and returns a IQueryFilter which is the result of any comparisons
/// between SonColumns and other values
/// </param>
/// <param name="db"></param>
public static long Count(WhereDelegate <SonColumns> where, Database database = null)
{
SonColumns c = new SonColumns();
IQueryFilter filter = where (c);
Database db = database ?? Db.For <Son>();
QuerySet query = GetQuerySet(db);
query.Count <Son>();
query.Where(filter);
query.Execute(db);
return(query.Results.As <CountResult>(0).Value);
}
/// <summary>
/// Get one entry matching the specified filter. If none exists
/// one will be created; success will depend on the nullability
/// of the specified columns.
/// </summary>
/// <param name="where"></param>
/// <param name="database"></param>
public static Son GetOneWhere(WhereDelegate <SonColumns> where, Database database = null)
{
var result = OneWhere(where, database);
if (result == null)
{
SonColumns c = new SonColumns();
IQueryFilter filter = where (c);
result = CreateFromFilter(filter, database);
}
return(result);
}
public static async Task BatchQuery(int batchSize, WhereDelegate <SonColumns> where, Action <IEnumerable <Son> > batchProcessor, Database database = null)
{
await Task.Run(async() =>
{
SonColumns columns = new SonColumns();
var orderBy = Order.By <SonColumns>(c => c.KeyColumn, SortOrder.Ascending);
var results = Top(batchSize, where, orderBy, database);
while (results.Count > 0)
{
await Task.Run(() =>
{
batchProcessor(results);
});
long topId = results.Select(d => d.Property <long>(columns.KeyColumn.ToString())).ToArray().Largest();
results = Top(batchSize, (SonColumns) where (columns) && columns.KeyColumn > topId, orderBy, database);
}
});
}
/// <summary>
/// Execute a query and return the specified number of values. This method
/// will issue a sql TOP clause so only the specified number of values
/// will be returned.
/// </summary>
/// <param name="count">The number of values to return.
/// This value is used in the sql query so no more than this
/// number of values will be returned by the database.
/// </param>
/// <param name="where">A WhereDelegate that recieves a SonColumns
/// and returns a IQueryFilter which is the result of any comparisons
/// between SonColumns and other values
/// </param>
/// <param name="orderBy">
/// Specifies what column and direction to order the results by
/// </param>
/// <param name="database"></param>
public static SonCollection Top(int count, WhereDelegate <SonColumns> where, OrderBy <SonColumns> orderBy, Database database = null)
{
SonColumns c = new SonColumns();
IQueryFilter filter = where (c);
Database db = database ?? Db.For <Son>();
QuerySet query = GetQuerySet(db);
query.Top <Son>(count);
query.Where(filter);
if (orderBy != null)
{
query.OrderBy <SonColumns>(orderBy);
}
query.Execute(db);
var results = query.Results.As <SonCollection>(0);
results.Database = db;
return(results);
}
