/*
* /// <summary>
* /// Returns a reader for the specified amount of rows for the specified entity type.
* /// </summary>
* /// <typeparam name="T">The type of entity to be queried.</typeparam>
* /// <param name="condition">An optional condition to allow querying for specific rows. Leave at null to query all rows.</param>
* /// <param name="amountOfRows">The amount of rows to be returned (maximum). Leave at -1 to query all rows.</param>
* /// <returns>A DbDataReader that has tried to query rows for entities of type T.</returns>
* internal DbDataReader GetReader<T>(BuiltSqlCondition condition = null, int amountOfRows = -1)
* {
* return GetReader(typeof(T), condition, amountOfRows);
* }
*
* /// <summary>
* /// Returns a reader for the specified amount of rows for the specified entity type.
* /// </summary>
* /// <param name="entityType">The type of entity to be queried.</param>
* /// <param name="condition">An optional condition to allow querying for specific rows. Leave at null to query all rows.</param>
* /// <param name="amountOfRows">The amount of rows to be returned (maximum). Leave at -1 to query all rows.</param>
* /// <returns>A DbDataReader that has tried to query rows for entities of type T.</returns>
* internal DbDataReader GetReader(Type entityType, BuiltSqlCondition condition = null, int amountOfRows = -1)
* {
* var select = SqlBuild.Select(entityType);
*
* if (condition != null)
* select.Condition = condition;
*
* if (amountOfRows > 0)
* select.Limit(amountOfRows);
*
* return select.GenerateCommand(_connection).ExecuteReader();
* }
*
* /// <summary>
* /// Returns a reader for the specified amount of rows for the specified entity type.
* /// </summary>
* /// <param name="entityType">The type of entity to be queried.</param>
* /// <param name="commandString">The command to execute to create the reader.</param>
* /// <returns>A DbDataReader that has tried to query rows for entities of type entityType.</returns>
* internal DbDataReader GetReader(Type entityType, string commandString)
* {
* using (var command = _connection.CreateCommand())
* {
* command.CommandText = commandString;
* return command.ExecuteReader();
* }
* }
*/
/// <summary>
/// Fetches and initializes all available rows for entities of type T.
/// </summary>
/// <typeparam name="T">The type of entity to be queried.</typeparam>
/// <param name="condition">An optional condition to allow querying for specific rows. Leave at null to query all rows.</param>
/// <returns>An enumerable of constructed entities of type T.</returns>
public IEnumerable <T> All <T>(BuiltSqlCondition condition = null) where T : new()
{
var command = _connection.CreateCommand();
command.CommandText = SqlBuild.Select <T>().GenerateStatement();
condition?.GenerateCommand(command);
var reader = command.ExecuteReader();
List <T> resultSet = new List <T>();
while (reader.Read())
{
resultSet.Add(BuildSingle <T>(reader));
}
command.Dispose();
return(resultSet);
}
/// <summary>
/// Fetches and initializes the specified number of rows for entities of type T.
/// </summary>
/// <typeparam name="T">The type of entity to be queried.</typeparam>
/// <param name="condition">An optional condition to allow querying for specific rows. Leave at null to query all rows.</param>
/// <param name="amountOfRows">The amount of rows to be queried (maximum).</param>
/// <returns>An enumerable of constructed entities of type T.</returns>
public IEnumerable <T> Fetch <T>(BuiltSqlCondition condition, int amountOfRows = -1) where T : new()
{
var select = SqlBuild.Select <T>();
select.Condition = condition;
if (amountOfRows != -1)
{
if (ProviderSpecific.SupportsLimit)
{
select.Limit(amountOfRows);
}
}
var command = select.GenerateCommand(_connection);
var reader = command.ExecuteReader();
List <T> resultSet = new List <T>();
if (!ProviderSpecific.SupportsLimit && amountOfRows != -1)
{
int rows = 0;
while (reader.Read() && rows < amountOfRows)
{
resultSet.Add(BuildSingle <T>(reader));
rows++;
}
}
else
{
while (reader.Read())
{
resultSet.Add(BuildSingle <T>(reader));
}
}
command.Dispose();
return(resultSet);
//var reader = GetReader<T>(condition, amountOfRows);
//List<T> resultSet = new List<T>();
while (reader.Read())
{
resultSet.Add(BuildSingle <T>(reader));
}
return(resultSet);
}
/// <summary>
/// Takes the current row that the reader is on and uses it to construct a new entity of type T.<para />
/// Does not alter the reader's cursor at all.
/// May return an incomplete entity in case of failure.
/// </summary>
/// <param name="tableType">The type of entity to be constructed.</param>
/// <param name="reader">The reader to be used. Make sure .HasRows is true before passing this in.</param>
/// <returns>The constructed entity of type T.</returns>
internal object BuildSingle(Type tableType, DbDataReader reader)
{
var propToCol = SqlTableHelper.PropertiesToColumnNames(tableType);
var entity = Activator.CreateInstance(tableType);
foreach (var property in propToCol)
{
var sqlColumnAttribute = property.Key.GetCustomAttribute <SqlColumn>();
if (sqlColumnAttribute != null && property.Key.GetCustomAttribute <SqlForeignKey>() == null)
{
switch (sqlColumnAttribute.Type)
{
case DbType.Int16:
case DbType.Int32:
case DbType.Int64:
property.Key.SetValue(entity, Convert.ToInt32(reader[property.Value]), null);
break;
case DbType.String:
case DbType.StringFixedLength:
case DbType.AnsiString:
case DbType.AnsiStringFixedLength:
string value = reader[property.Value].ToString();
property.Key.SetValue(entity, value, null);
break;
case DbType.Date:
case DbType.DateTime:
case DbType.DateTime2:
case DbType.DateTimeOffset:
string stringValue = reader[property.Value].ToString();
DateTime dateValue = DateTime.ParseExact(stringValue, ProviderSpecific.DotNetDateFormatString, CultureInfo.InvariantCulture);
property.Key.SetValue(entity, dateValue, null);
break;
default:
throw new Exception("Unsupported column type.");
}
}
if (sqlColumnAttribute == null)
{
continue;
}
var sqlForeignKeyAttributes = property.Key.GetCustomAttributes <SqlForeignKey>();
foreach (var foreignKey in sqlForeignKeyAttributes)
{
Type foreignTable = foreignKey.ForeignTable;
var properties = foreignTable.GetProperties();
foreach (var prop in properties)
{
var attrib = prop.GetCustomAttribute <SqlColumn>();
if (attrib == null)
{
continue;
}
if (attrib.ColumnName == foreignKey.ForeignTableColumnName)
{
var foreignSelect = SqlBuild.Select(foreignTable)
.Join(tableType, foreignTable, sqlColumnAttribute.ColumnName, foreignKey.ForeignTableColumnName)
.Where(
new BuiltSqlCondition()
.AddCondition(tableType, sqlColumnAttribute.ColumnName, "=", (string)reader[sqlColumnAttribute.ColumnName], sqlColumnAttribute.Type));
var foreignReader = foreignSelect.GenerateCommand(_connection).ExecuteReader();
if (!foreignReader.Read())
{
continue;
}
var foreignEntity = BuildSingle(foreignTable, foreignReader);
property.Key.SetValue(entity, foreignEntity);
break;
}
}
}
}
return(entity);
}
