public override void DoBulkInsert <T>(Table <T> table, List <T> rows, IDbConnection connection)
{
int pageSize = UseBulkInsert[table];
//ProjectionData projData = ProjectionData.FromReflectedType(typeof(T));
ProjectionData projData = AttribHelper.GetProjectionData(typeof(T));
TableAttribute tableAttrib = typeof(T).GetCustomAttributes(false).OfType <TableAttribute>().Single();
//build "INSERT INTO products (ProductName, SupplierID, CategoryID, QuantityPerUnit)"
string header = "INSERT INTO " + tableAttrib.Name + " " + InsertClauseBuilder.InsertRowHeader(projData);
foreach (List <T> page in Page.Paginate(rows, pageSize))
{
int numFieldsAdded = 0;
StringBuilder sbValues = new StringBuilder(" VALUES ");
List <IDbDataParameter> paramList = new List <IDbDataParameter>();
IDbCommand cmd = connection.CreateCommand();
//package up all fields in N rows:
string separator = "";
foreach (T row in page)
{
//prepare values = "(?P1, ?P2, ?P3, ?P4)"
string values =
InsertClauseBuilder.InsertRowFields(this, cmd, row, projData, paramList, ref numFieldsAdded);
sbValues.Append(separator).Append(values);
separator = ", ";
}
string sql = header + sbValues; //'INSET t1 (field1) VALUES (11),(12)'
cmd.CommandText = sql;
paramList.ForEach(param => cmd.Parameters.Add(param));
int result = cmd.ExecuteNonQuery();
}
}
/// <summary>
/// Quote from MSDN:
/// If the object requested by the query is easily identifiable as one
/// already retrieved, no query is executed. The identity table acts as a cache
/// of all previously retrieved objects
/// From Matt Warren: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=345635&SiteID=1
/// The cache is checked when the query is a simple table.Where(pred) or table.First(pred) where the
/// predicate refers only to the primary key. Otherwise the query is always sent and the cache only checked
/// after the results are retrieved.
/// The DLINQ cache is not distributed or shared, it is local and contained within the context. It is only a
/// referential identity cache used to guarantee that two reads of the same entity return the same instance.
/// You are not expected to hold the cache for an extended duration (except possibly for a client scenario),
/// or share it across threads, processes, or machines in a cluster.
/// </summary>
public static bool TryRetrieveFromCache <S>(SessionVarsParsed vars, Expression scalarExpr, out S cachedRow)
{
cachedRow = default(S);
int count1 = vars.ExpressionChain.Count;
MethodCallExpression scalarMethodCall = scalarExpr.XMethodCall();
bool isSingleWhere = false;
LambdaExpression whereLambda = null;
if (count1 == 1 && scalarMethodCall.Arguments.Count == 1)
{
MethodCallExpression call0 = vars.ExpressionChain[0];
if (call0.Method.Name == "Where" && call0.Arguments.Count == 2)
{
//db.Customers.Where(id==1).Single()
isSingleWhere = true;
whereLambda = call0.Arguments[1].XLambda();
}
}
else if (count1 == 0 && scalarMethodCall.Arguments.Count == 2)
{
//db.Customers.Single(id==1)
isSingleWhere = true;
whereLambda = scalarMethodCall.Arguments[1].XLambda();
}
if ((!isSingleWhere) || whereLambda == null)
{
return(false);
}
if (whereLambda.Parameters.Count != 1 || whereLambda.Parameters[0].NodeType != ExpressionType.Parameter)
{
return(false);
}
if (whereLambda.Body.NodeType != ExpressionType.Equal)
{
return(false);
}
BinaryExpression equals = (BinaryExpression)whereLambda.Body;
Expression left = equals.Left;
Expression right = equals.Right;
MemberExpression member;
ConstantExpression consta;
if (left.NodeType == ExpressionType.MemberAccess && right.NodeType == ExpressionType.Constant)
{
member = left.XMember();
consta = right.XConstant();
}
else if (left.NodeType == ExpressionType.Constant && right.NodeType == ExpressionType.Parameter)
{
member = right.XMember();
consta = left.XConstant();
}
else
{
return(false);
}
if (member.Expression.NodeType != ExpressionType.Parameter)
{
return(false);
}
//check that it's a primary key field
ColumnAttribute colAttrib = AttribHelper.GetColumnAttribute(member.Member);
if (colAttrib == null)
{
return(false);
}
if (!colAttrib.IsPrimaryKey)
{
return(false);
}
IdentityKey key = new IdentityKey(typeof(S), consta.Value);
DataContext context = vars.Context;
object cachedEntity = context.GetRegisteredEntityByKey(key);
if (cachedEntity == null)
{
return(false);
}
cachedRow = (S)cachedEntity;
return(true);
}
