Entity Framework learning Accumulation

From: http://www.cnblogs.com/mbailing/archive/2012/07/16/2593368.html

 

Tips for using ef4.1/4.3

(1) Multi-table join query statement:

VaR query = (from m in context. dic_propertyclassdef.include ("dic_propertytypedef ")
. Include ("dic_propertytypedef.dic_propertyvaluedef ")
. Include ("dic_propertytypedef.dic_propertyoptvaluedef ")

This is a multi-table join query statement. You can keep incude. However, it is recommended that you use SQL or stored procedures for complicated services.

(2) The in statement in ef4.1/4.3:

VaR query = Entities. Where (P => IDs. Contains (P. ID ));
IDS is the ID column you passed in this sentence. It can be an array or a wildcard (list <int>)

(3) paging in EF

Query. orderbydescending (r => r. propid). Skip (startrowindex). Take (maximumrows). tolist ();

Startrowindex is the starting index and the number of maximumrows to query. For example, startrowindex = 0 and maximumrows = 10 are 10 records starting from 0.

EF distribution must be used with orderbydescending.