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 336     <li><a href="../../docs/java/tools/ant.html">Using Apache Ant</a></li>
 337     <li><a href="../../docs/java/tools/localunittesting.html">Local Unit Testing</a>
 338         <ul>
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 360           <li><a href="../../docs/python/overview.html">Overview</a></li>
 361     <li><a href="../../docs/python/runtime.html">CGI Environment</a></li>
 362     <li><a href="../../docs/python/datastore/index.html">Storing Data</a>
 363       <ul>
 364              <li><a href="../../docs/python/datastore/overview.html">Overview</a></li>
 365      <li><a href="../../docs/python/datastore/entitiesandmodels.html">Entities and Models</a></li>
 366      <li><a href="../../docs/python/datastore/creatinggettinganddeletingdata.html">Creating, Getting and Deleting Data</a></li>
 367      <li><a href="../../docs/python/datastore/keysandentitygroups.html">Keys and Entity Groups</a></li>
 368      <li><a href="../../docs/python/datastore/queriesandindexes.html">Queries and Indexes</a></li>
 369      <li><a href="../../docs/python/datastore/transactions.html">Transactions</a></li>
 370      <li><a href="../../docs/python/datastore/typesandpropertyclasses.html">Types and Property Classes</a></li>
 371      <li><a href="../../docs/python/datastore/gqlreference.html">GQL Reference</a></li>
 372      <li><a href="../../docs/python/datastore/stats.html">Statistics</a></li>
 373
 374      <li><span class="tlw-title tlw-expanded">Reference</span>
 375        <ul>
 376          <li><a href="../../docs/python/datastore/modelclass.html">Model</a></li>
 377          <li><a href="../../docs/python/datastore/expandoclass.html">Expando</a></li>
 378          <li><a href="../../docs/python/datastore/polymodelclass.html">PolyModel</a></li>
 379          <li><a href="../../docs/python/datastore/propertyclass.html">Property</a></li>
 380          <li><a href="../../docs/python/datastore/queryclass.html">Query</a></li>
 381          <li><a href="../../docs/python/datastore/gqlqueryclass.html">GqlQuery</a></li>
 382          <li><a href="../../docs/python/datastore/keyclass.html">Key</a></li>
 383          <li><a href="../../docs/python/datastore/functions.html">Functions</a></li>
 384          <li><a href="../../docs/python/datastore/exceptions.html">Exceptions</a></li>
 385        </ul>
 386      </li>
 387
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 389     </li>
 390     <li><a href="../../docs/python/apis.html">Services</a>
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 392         <li><a href="../../docs/python/blobstore/index.html">Blobstore</a>
 393           <ul>
 394             <li><a href="../../docs/python/blobstore/overview.html">Overview</a></li>
 395 <li><span class="tlw-title tlw-expanded">Reference</span>
 396   <ul>
 397     <li><a href="../../docs/python/blobstore/blobinfoclass.html">BlobInfo</a></li>
 398     <li><a href="../../docs/python/blobstore/blobkeyclass.html">BlobKey</a></li>
 399     <li><a href="../../docs/python/blobstore/blobreaderclass.html">BlobReader</a></li>
 400     <li><a href="../../docs/python/blobstore/functions.html">Functions</a></li>
 401     <li><a href="../../docs/python/blobstore/exceptions.html">Exceptions</a></li>
 402   </ul>
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 404
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 406         </li>
 407         <li><a href="../../docs/python/images/index.html">Images</a>
 408           <ul>
 409                  <li><a href="../../docs/python/images/overview.html">Overview</a></li>
 410      <li><a href="../../docs/python/images/installingPIL.html">Installing PIL</a></li>
 411      <li><a href="../../docs/python/images/usingimages.html">Using the Images API</a></li>
 412      <li><span class="tlw-title tlw-expanded">Reference</span>
 413        <ul>
 414          <li><a href="../../docs/python/images/imageclass.html">Image</a></li>
 415          <li><a href="../../docs/python/images/functions.html">Functions</a></li>
 416          <li><a href="../../docs/python/images/exceptions.html">Exceptions</a></li>
 417        </ul>
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 421         </li>
 422         <li><a href="../../docs/python/mail/index.html">Mail</a>
 423           <ul>
 424                  <li><a href="../../docs/python/mail/overview.html">Overview</a></li>
 425      <li><a href="../../docs/python/mail/sendingmail.html">Sending Mail</a></li>
 426      <li><a href="../../docs/python/mail/receivingmail.html">Receiving Mail</a></li>
 427      <li><a href="../../docs/python/mail/attachments.html">Attachments</a></li>
 428      <li><span class="tlw-title tlw-expanded">Reference</span>
 429        <ul>
 430          <li><a href="../../docs/python/mail/emailmessageclass.html">EmailMessage</a></li>
 431          <li><a href="../../docs/python/mail/emailmessagefields.html">Message Fields</a></li>
 432          <li><a href="../../docs/python/mail/functions.html">Functions</a></li>
 433          <li><a href="../../docs/python/mail/exceptions.html">Exceptions</a></li>
 434        </ul>
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 439         <li><a href="../../docs/python/memcache/index.html">Memcache</a>
 440           <ul>
 441                  <li><a href="../../docs/python/memcache/overview.html">Overview</a></li>
 442       <li><a href="../../docs/python/memcache/usingmemcache.html">Using Memcache</a></li>
 443      <li><span class="tlw-title tlw-expanded">Reference</span>
 444        <ul>
 445          <li><a href="../../docs/python/memcache/clientclass.html">Client</a></li>
 446          <li><a href="../../docs/python/memcache/functions.html">Functions</a></li>
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 451         </li>
 452         <li><a href="../../docs/python/multitenancy/index.html">Multitenancy</a>
 453           <ul>
 454                   <li><a href="../../docs/python/multitenancy/overview.html">Overview</a></li>
 455     <li><a href="../../docs/python/multitenancy/multitenancy.html">Multitenancy with Namespaces</a></li>
 456     <li><a href="../../docs/python/multitenancy/namespaces.html">Other Uses for Namespaces</a></li>
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 466         <li><a href="../../docs/python/oauth/index.html">OAuth</a>
 467           <ul>
 468                  <li><a href="../../docs/python/oauth/overview.html">Overview</a></li>
 469      <li><span class="tlw-title tlw-expanded">Reference</span>
 470        <ul>
 471          <li><a href="../../docs/python/oauth/functions.html">Functions</a></li>
 472          <li><a href="../../docs/python/oauth/exceptions.html">Exceptions</a></li>
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 477         </li>
 478         <li><a href="../../docs/python/taskqueue/index.html">Task Queues</a>
 479           <ul>
 480                  <li><a href="../../docs/python/taskqueue/overview.html">Overview</a></li>
 481      <li><span class="tlw-title tlw-expanded">Reference</span>
 482        <ul>
 483          <li><a href="../../docs/python/taskqueue/tasks.html">Task Class</a></li>
 484          <li><a href="../../docs/python/taskqueue/queues.html">Queue Class</a></li>
 485          <li><a href="../../docs/python/taskqueue/functions.html">Functions</a></li>
 486          <li><a href="../../docs/python/taskqueue/exceptions.html">Exceptions</a></li>
 487        </ul>
 488      </li>
 489
 490           </ul>
 491         </li>
 492         <li><a href="../../docs/python/urlfetch/index.html">URL Fetch</a>
 493           <ul>
 494                  <li><a href="../../docs/python/urlfetch/overview.html">Overview</a></li>
 495      <li><span class="tlw-title tlw-expanded">Reference</span>
 496        <ul>
 497          <li><a href="../../docs/python/urlfetch/fetchfunction.html">The fetch Function</a></li>
 498          <li><a href="../../docs/python/urlfetch/asynchronousrequests.html">Asynchronous Requests</a></li>
 499          <li><a href="../../docs/python/urlfetch/responseobjects.html">Response Objects</a></li>
 500          <li><a href="../../docs/python/urlfetch/exceptions.html">Exceptions</a></li>
 501        </ul>
 502      </li>
 503
 504           </ul>
 505         </li>
 506         <li><a href="../../docs/python/users/index.html">Users</a>
 507           <ul>
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 510      <li><a href="../../docs/python/users/loginurls.html">Login URLs</a></li>
 511      <li><a href="../../docs/python/users/adminusers.html">Admin Users</a></li>
 512
 513      <li><span class="tlw-title tlw-expanded">Reference</span>
 514        <ul>
 515          <li><a href="../../docs/python/users/userclass.html">User</a></li>
 516          <li><a href="../../docs/python/users/functions.html">Functions</a></li>
 517          <li><a href="../../docs/python/users/exceptions.html">Exceptions</a></li>
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 524           <ul>
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 529          <li><a href="../../docs/python/xmpp/messageclass.html">Message</a></li>
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 531        </ul>
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 533
 534           </ul>
 535         </li>
 536       </ul>
 537     </li>
 538     <li><a href="../../docs/python/config/index.html">Configuration</a>
 539       <ul>
 540             <li><a href="../../docs/python/config/appconfig.html">App Config</a></li>
 541     <li><a href="../../docs/python/config/indexconfig.html">Index Config</a></li>
 542     <li><a href="../../docs/python/config/cron.html">Scheduled Tasks</a></li>
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 553     <li><a href="../../docs/python/tools/webapp/index.html">webapp Framework</a>
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 555              <li><a href="../../docs/python/tools/webapp/overview.html">Overview</a></li>
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 558      <li><a href="../../docs/python/tools/webapp/requestdata.html">Request Data</a></li>
 559      <li><a href="../../docs/python/tools/webapp/buildingtheresponse.html">Building the Response</a></li>
 560      <li><a href="../../docs/python/tools/webapp/redirects.html">Redirects, Headers and Status Codes</a></li>
 561      <li><a href="../../docs/python/tools/webapp/blobstorehandlers.html">Blobstore Handlers</a></li>
 562
 563      <li><span class="tlw-title tlw-expanded">Reference</span>
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 565          <li><a href="../../docs/python/tools/webapp/requestclass.html">Request</a></li>
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 614       <li>Launcher Code
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 627   <li><a href="http://code.google.com/p/googleappengine/wiki/SdkReleaseNotes">Release Notes: Python</a></li>
 628   <li><a href="http://code.google.com/p/googleappengine/wiki/SdkForJavaReleaseNotes">Release Notes: Java</a></li>
 629   <li><a href="../../docs/revision_history.html">Revision History</a></li>
 630 </ul>
 631
 632         <a class="hidden" href="#gc-topnav-anchor">More Google App Engine resource links</a>
 633       </div>
 634
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 636       <div class="g-unit" id="gc-pagecontent">
 637         <script type="text/javascript">CODESITE_docEarlyProcessing();</script>
 638         <h1 class="page_title">Mastering the datastore</h1>
 639
 640
 641
 642 <div id="jd-content">
 643 <div class="jd-descr">
 644
 645 <p>Unlike most other Java web application development environments, App Engine's data storage service is not based on a relational database management system. Instead, App Engine's datastore (<a href="../../docs/python/datastore/index.html">Python</a> | <a href="../../docs/java/datastore/index.html">Java</a>) is built on top of <a href="http://labs.google.com/papers/bigtable.html">Bigtable</a>, and this will likely require you to re-think the methods that you have traditionally used when modeling and querying for data.</p>
 646
 647 <p>In this article series, we aim to provide information supplementary to the datastore documentation that should help provide a better understanding of how the datastore works, how to deal with issues related to using a distributed storage system, and provide best practices on techniques to model and retrieve your data. The articles in this series include:</p>
 648
 649 <p>
 650 <dl>
 651   <dt><a href="../life_of_write.html">Life of a Datastore Write</a></dt>
 652   <dd>Learn everything that occurs behind-the-scenes when an entity is written to the datastore</dd>
 653   <dt><a href="../transaction_isolation.html">Transaction Isolation in App Engine</a></dt>
 654   <dd>Explains how concurrent reads and writes behave both in and outside of transactions</dd>
 655   <dt><a href="../index_building.html">How Index Building Works</a></dt>
 656   <dd>Explains the back-end processes used to build and delete composite indexes</dd>
 657   <dt><a href="../storage_breakdown.html">How Entities and Indexes are Stored</a></dt>
 658   <dd>Provides detailed descriptions of the Bigtables used to store entities and indexes</dd>
 659   <dt><a href="../modeling.html">Modeling Entity Relationships</a></dt>
 660   <dd>Explains the basics of modeling entity relationships</dd>
 661   <dt><a href="../update_schema.html">Updating Your Model's Schema</a></dt>
 662   <dd>Discusses strategies for updating datastore schemas</dd>
 663   <dt><a href="../handling_datastore_errors.html">Handling Datastore Errors</a></dt>
 664   <dd>Learn why datastore errors occur and how to deal with them</dd>
 665 </dl>
 666 </p>
 667
 668 </div></div>
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