Method ExecuteReaderCQ

ExecuteReaderCQ(ContinuousQuery)

Opens ExecuteReader(String, IDictionary, Boolean, Int32) on server nodes to execute query, also registers continuous query call backs for data, that falls on query's criteria; if any changes occur in that data.

Declaration

public virtual ICacheReader ExecuteReaderCQ(ContinuousQuery cquery)

Parameters

Type	Name	Description
ContinuousQuery	cquery	simple SQL like query syntax to query objects from cache

Returns

Type	Description
ICacheReader	Returns a cache reader of first chunk of data on execution of data reader

Examples

These operators are supported by NCache Queries.

Comparison Operators = , == , != , <> , < , > , <=, >=, IN
Logical Operators AND , OR , NOT
Miscellaneous () , DateTime.Now , DateTime("any date time compatible string")

Cache _cache = NCache.InitializeCache("mycache");

product1 = new Product(3, "Tunnbr?d", "", 4, 2);
product2 = new Product(4, "Tunnbr?d", "", 5, 9);
string qry = "SELECT Product WHERE this.ProductQuantity = ?;"
Hashtable indexTable = new Hashtable();
indexTable.Add("ProductQuantity", 9);
ContinuousQuery cQuery = new ContinuousQuery(qry, indexTable);

_cache.Add("2202", product1);
_cache.Add("2203", product2);
cQuery.RegisterNotification(new QueryDataNotificationCallback(QueryItemCallBack), EventType.ItemUpdated | EventType.ItemRemoved, EventDataFilter.None); 

ICacheReader reader = _cache.ExecuteReaderCQ(cQuery);
 if (reader.FieldCount > 0)
      {
          while (reader.Read())
          {
             object category = reader.GetValue(0);
              //perform operations
          }
      }
 else
      {
         //perform operations
      }
 reader.Close();

public void QueryItemCallBack(string key, CQEventArg arg)
{
    switch (arg.EventType)
     {
        case EventType.ItemRemoved:
          //do something
           break;
        case EventType.ItemUpdated:
         //do something
           break;
        case EventType.ItemAdded:
          //do something
           break;
      }
}

ExecuteReaderCQ(ContinuousQuery, Boolean)

Declaration

public virtual ICacheReader ExecuteReaderCQ(ContinuousQuery cquery, bool getData)

Parameters

Type	Name	Description
ContinuousQuery	cquery	simple SQL like query syntax to query objects from cache
System.Boolean	getData	Flag to receive the values/data along with keys

Returns

Type	Description
ICacheReader	Returns a cache reader of first chunk of data on execution of data reader

Examples

These operators are supported by NCache Queries.

Comparison Operators = , == , != , <> , < , > , <=, >=, IN
Logical Operators AND , OR , NOT
Miscellaneous () , DateTime.Now , DateTime("any date time compatible string")

Cache _cache = NCache.InitializeCache("mycache");

product1 = new Product(3, "Tunnbr?d", "", 4, 2);
product2 = new Product(4, "Tunnbr?d", "", 5, 9);
string qry = "SELECT Product WHERE this.ProductID = ?;"
Hashtable indexTable = new Hashtable();
indexTable.Add("ProductID", 4);
ContinuousQuery cQuery = new ContinuousQuery(qry, indexTable);

_cache.Add("2202", product1);
_cache.Add("2203", product2);
cQuery.RegisterNotification(new QueryDataNotificationCallback(QueryItemCallBack), EventType.ItemUpdated | EventType.ItemRemoved, EventDataFilter.None); 

ICacheReader reader = _cache.ExecuteReaderCQ(cQuery,true);

if (reader.FieldCount > 0)
    {
     while (reader.Read())
      {
        object category = reader.GetValue(0);
        //perform operations
      }
    }
else
    {
        //perform operations
    }
reader.Close();

public void QueryItemCallBack(string key, CQEventArg arg)
{
    switch (arg.EventType)
     {
        case EventType.ItemRemoved:
          //do something
           break;
        case EventType.ItemUpdated:
         //do something
           break;
        case EventType.ItemAdded:
          //do something
           break;
      }
}

ExecuteReaderCQ(ContinuousQuery, Boolean, Int32)

Opens ExecuteReader(String, IDictionary, Boolean, Int32) on server nodes to execute query, also registers call backs for data, that falls on query's criteria; if any changes occur in that data. Flag for getting data and chunk size can be set by using this overload.

Declaration

public virtual ICacheReader ExecuteReaderCQ(ContinuousQuery query, bool getData, int chunkSize)

Parameters

Type	Name	Description
ContinuousQuery	query	simple SQL like query syntax to query objects from cache
System.Boolean	getData	Flag to receive the values/data along with keys
System.Int32	chunkSize	Size of data/keys packets received after search, default value is 512 * 1024 kb's

Returns

Type	Description
ICacheReader	Returns a cache reader of first chunk of data on execution of data reader

Examples

These operators are supported by NCache Queries.

Comparison Operators = , == , != , <> , < , > , <=, >=, IN
Logical Operators AND , OR , NOT
Miscellaneous () , DateTime.Now , DateTime("any date time compatible string")

Cache _cache = NCache.InitializeCache("mycache");

product1 = new Product(3, "Tunnbr?d", "", 4, 2);
product2 = new Product(4, "Tunnbr?d", "", 5, 9);
string qry = "SELECT Product where this.ProductName = ?";
Hashtable indexTable = new Hashtable();
indexTable.Add("ProductName", "Tunnbr?d");
ContinuousQuery cQuery = new ContinuousQuery(qry, indexTable);

_cache.Add("2202", product1);
_cache.Add("2203", product2);

cQuery.RegisterNotification(new QueryDataNotificationCallback(QueryItemCallBack), EventType.ItemUpdated | EventType.ItemRemoved, EventDataFilter.None); 

ICacheReader reader = _cache.ExecuteReaderCQ(cQuery,true,50);
if (reader.FieldCount > 0)
    {
        while (reader.Read())
        {
            object category = reader.GetValue(0);
            //perform operations
         }
    }
else
    {
      //perform operations
    }
reader.Close();

public void QueryItemCallBack(string key, CQEventArg arg)
{
    switch (arg.EventType)
     {
        case EventType.ItemRemoved:
          //do something
           break;
        case EventType.ItemUpdated:
         //do something
           break;
        case EventType.ItemAdded:
          //do something
           break;
      }
}