/// <summary>
/// Converts any Database instance into a queryable database.
/// </summary>
/// <param name="db"></param>
/// <returns>Queryable database instance that operates on the same
/// MSI handle.</returns>
/// <remarks>
/// This extension method is meant for convenient on-the-fly conversion.
/// If the existing database instance already happens to be a QDatabase,
/// then it is returned unchanged. Otherwise since the new database
/// carries the same MSI handle, only one of the instances needs to be
/// closed, not both.
/// </remarks>
public static QDatabase AsQueryable(this Database db)
{
QDatabase qdb = db as QDatabase;
if (qdb == null && db != null)
{
qdb = new QDatabase(db.Handle, true, db.FilePath, db.OpenMode);
}
return(qdb);
}
internal Query(QDatabase db, Expression expression)
{
if (expression == null)
{
throw new ArgumentNullException("expression");
}
this.db = db;
this.queryableExpression = expression;
this.tables = new List <TableInfo>();
this.recordTypes = new List <Type>();
this.selectors = new List <string>();
this.whereParameters = new List <object>();
this.orderbyColumns = new List <TableColumn>();
this.selectColumns = new List <TableColumn>();
this.joinColumns = new List <TableColumn>();
this.projectionDelegates = new List <Delegate>();
}
/// <summary>
/// Creates a new QTable with an explicit table name.
/// </summary>
/// <param name="db">database that contains the table</param>
/// <param name="table">name of the table</param>
public QTable(QDatabase db, string table)
{
if (db == null)
{
throw new ArgumentNullException("db");
}
if (string.IsNullOrWhiteSpace(table))
{
throw new ArgumentNullException("table");
}
this.db = db;
this.tableInfo = db.Tables[table];
if (this.tableInfo == null)
{
throw new ArgumentException(
"Table does not exist in database: " + table);
}
}
/// <summary>
/// Creates a new QTable, inferring the table name
/// from the name of the record type parameter.
/// </summary>
/// <param name="db">database that contains the table</param>
public QTable(QDatabase db)
: this(db, InferTableName())
{
}