Principle and Implementation interpreter mode of Atitit. linq java, atitit. linq Interpreter
Principles and implementation interpreter mode of Atitit. linq java
1. Implementation of Linq from where 1
2. Where expr Implementation 1
3. A variation of Attilax 2
4. interpreter mode structure 2
5. Code3
5.1. EqExpression3
Due to the limited time yesterday, there are still some follow-up. To maintain the habit of summing up and writing blogs on a daily basis, I have finished the basics of the LinQ technology today, the rest is to see how we can make the best use of it.
Today's highlights:
1. Concurrent management mechanism of LinQ to Entity
2. Implementation of LinQ to DataSet
This article is organized from the msdn
I. Concepts of LINQ:LINQ is short for Language Integrated Query (Language integration query), which is integrated in. netProgramming LanguageThis allows the query expression to get a good syntax check during compilation, rich metadata, and advantages of smart sensing for other strong languages. net Framework Version 3.5 is a groundbreaking innovation that builds a bridge between the object field and the data field.
Ii. Background of the emergence of LI
Recently, an article published by Elisa Flasko on MSDN compares the applicable scenarios of LINQ to SQL and LINQ to Entities:
Introducing LINQ to Relational Data
Http://msdn2.microsoft.com/en-us/library/cc161164.aspx
The author points out that the main application scenarios of LINQ to SQL are the rapid development of M
Recently, an article published by ELISA flasko on msdn compares the applicable scenarios of LINQ to SQL and LINQ to entities:Introducing LINQ to Relational DataHttp://msdn2.microsoft.com/en-us/library/cc161164.aspx
The author points out that the main application scenarios of LINQ to SQL are the rapid development of Mic
ArticleDirectory
1. Get start
2. latency mechanism (deferred/lazy execution)
3. subquery)
Language Integrated Query is a group of technical names that allow us to write type-safe query statements to query local objects or remote data sets. The premise of using LINQ is that the collection you need to query implements the ienumerable ProgramExtend the implementation of LINQ, for example,
ArticleDirectory
Overview of the linq to XML class
LINQ to XML learning-2. Overview of LINQ to XML programming overview of the linq to XML class overview of the xattribute class
Xattribute indicates an XML Attribute. Xcdata class
Xcdata indicates a CDATA text node. Xcomment class
Xcomment indicates an X
Hi: The following is a LINQ to JS share, if there is a coincidence is purely coincidental(function () {Array.prototype.first = function (predicate, def) {var l = this.length; if (!predicate) return l? This[0]: def = = null? Null:def; for (var i = 0; i How to use: List.first (function (t) {return T.value.trim () = = City.trim ();}); JS simulation expands C # LINQ expressions to share
Label: style blog color Io AR for strong SP Div
Grouping refers to grouping values or elements in a sequence based on a specific value. LINQ only contains one grouping OPERATOR: groupby.
Groupby
1>. Prototype Definition
Public static iqueryable
2>. Example
VaR expr = from P in context. products Group P by P. categoryid; foreach (VAR item in expr) {foreach (var p in item) {console. writeline (P. productname );}}
VaR expr = context. Cities. grou
This article mainly describes attributes-based Linq ing of Linq to SQL. That is, ing database, ing table, ing column, ing relationship, ing stored procedure,
Ing function. However, there are three ways to create such mappings: ORD, SQLMetal, and manual code.
Create.
First, let's understand how to manually create property ing so that you can understand the code generated based on the tool. Their differenc
Combination of Linq groups and linq groups
There is a List, which requires grouping by date and combining the data of the same day with the implementation of Linq.
namespace ConsoleApplication1{ class Program { static void Main(string[] args) { List
We can see that the data items are grouped by date, and the data items of other a
And then, in this section, I'm going to lead you through the rest of the LINQ syntax. OK, no more nonsense, get to the point.
1, Cast, oftype operator
Cast and OfType: are used to convert a collection object of type IEnumerable to a collection object of type ienumerable
Here's an example from the previous section: (This example is referenced from Rookie_j blog)
Create a new ArrayList object first
ArrayList ArrayList = new ArrayList ()
{
New Person ()
We use a database of hotel management systems as an exampleTable structure is simple: guestinfo (guest information table), Room (rooms table), Roomtype (room type table), Hotelinfo (monthly earnings information)As a whole, there is a foreign key to the room type ID, and a foreign key for the ID of the room in the guest table. Monthly earnings information regardless of firstPreparation: New Project LINQ_CH4 console program, new DB folderRight-click the DB folder, add → new itemSelect the
Microsoft has launched LINQ in. NET 3.5. Now the various LINQ providers are full of flying sky. I saw a list of LINQ providers on the foreigner site just now, with more than 30:
LINQ to Amazon
LINQ to Active Directory
LINQ to Bind
As a breakthrough innovation in. NET Framework 3.5, LINQ builds a bridge between the object field and the data field, allowing you to conveniently operate data using lambda expressions .. Net Framework 3.5 has integrated the following functions, this allows you to implement your own LINQ solution for different data sources. Therefore, "LINQ to anything" is also p
1. Anonymous typeBy defining an anonymous type with the keyword VAR, the compiler emits a strong type based on the value of the expression on the right side of the operator.Some basic rules to follow when using anonymous types:◊ An anonymous type must have an initialization value, and the value cannot be null (NULL), because the type is inferred from the initializer;◊ Anonymous types can be used for simple types, or for complex types. When defining a simple type, it is of little value. Compound
Object ID
Objects in the Runtime Library have a unique identifier. Two variables that reference the same object actually reference the same instance of this object. After you change a variable, you can see the changes through another variable.
The row in the relational database table does not have a unique identifier. Because each row has a unique primary key, no two rows share the same key value.
In fact, we usually extract data from the database and put it into another layer, where the app
From this article, we should summarize the application of LINQ in practice. The first thing we should summarize is the combination of LINQ to objects, that is, the use of LINQ with program objects.
The most typical application object set is to use it with arrays, as shown in the following example:
1 class Program2 {3 static void main (string [] ARGs)4 {5 Int []
In. net 4.0, the dynamic type is provided for us. It can be a smart type, so we can generate an object class at runtime, then generate a method to obtain the set, and finally call it dynamically.
There is no more simple access method than this. You can try it by yourself. first look at the code, so that we will no longer envy linq to entiy.
QQ Group technical exchange:225656797
Let's look at Moon's design.
1. Database (sqlite)
Create table [Person]
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