Generated DbContext find namespace !

As stated in the EDM to add code generation item
chose ADO.NET DbContext Generator
generate Context.cs not find the file namespace "System.Data.Entity.Infrastructure".

found the next say Tools -> Library Package Manager -> Add Library Package Reference
But my 2010 tools simply had no Library Package Manager this option.
solved ! ! !
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that thing looks to be installed separately
Tools - > Extension Manager installed NuGet Package Manager on yo a
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an answer no sad reminder !
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tools - > extension Manager -> Add Library Package Reference-> online Library

in the rightmost search box input EF 4.x DbContext later, in the middle of the content area will appear you are looking for plug-ins,

selected plug-ins you want , click on the lower right corner of the "Add " button
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above answer your question because replication , gave the wrong answer. I did not have permission to modify , re- answer correct answer is as follows:

Tools - > Extension Manager - > Online Library ( above answer should be no "Add Library Package Reference")

in the rightmost search box input EF 4.x DbContext later, in the middle of the content area will appear you are looking for plug-ins,

selected plug-ins you want , click on the lower right corner of the "Add " button
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that is because you have not referenced EntityFramework.dll this file ,
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Why , after I installed or not , ah, I took down from svn 's