| <!doctype html> |
| <html> |
| <head> |
| <meta charset="utf-8"> |
| <!-- Always force latest IE rendering engine or request Chrome Frame --> |
| <meta content="IE=edge,chrome=1" http-equiv="X-UA-Compatible"> |
| |
| |
| <link href='https://fonts.googleapis.com/css?family=Source+Sans+Pro:300,300italic,400italic,400,600' rel='stylesheet' type='text/css'> |
| <!-- Use title if it's in the page YAML frontmatter --> |
| <title> |
| Remote Queries | |
| Geode Native C++ Docs |
| </title> |
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> |
| <link href="/stylesheets/all.css" rel="stylesheet" media="screen, print" /> |
| <link href="/stylesheets/print.css" rel="stylesheet" media="print" /> |
| <link href='/images/favicon.ico' rel='shortcut icon'> |
| |
| <script src="/javascripts/all.js"></script> |
| |
| </head> |
| |
| <body class="docs docs_geode-native docs_geode-native_cpp docs_geode-native_cpp_113 docs_geode-native_cpp_113_remote-queries has-subnav"> |
| |
| <div class="viewport"> |
| <div class='wrap'> |
| <script type="text/javascript"> |
| document.domain = "apache.org"; |
| </script> |
| |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <header class="header header-layout"> |
| <h1 class="logo"> |
| <a href="/"> |
| <img src="/images/Apache_Geode_logo_symbol_white.png" style="width:30px;"> |
| Apache Geode Native C++ Documentation |
| </a> |
| </h1> |
| <div class="header-links js-bar-links"> |
| <div class="btn-menu" data-behavior="MenuMobile"></div> |
| <div class="header-item"><a href="http://geode.apache.org">Back to Product Page</a></div> |
| <div class="header-item"> |
| <a href="http://geode.apache.org/community" target="_blank">Community</a> |
| </div> |
| </div> |
| </header> |
| |
| |
| <div class="container"> |
| |
| <!--googleoff: index--> |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <div id="sub-nav" class="js-sidenav nav-container" role="navigation"> |
| <a class="sidenav-title" data-behavior="SubMenuMobile">Doc Index</a> |
| <div class="nav-content"> |
| <ul> |
| <li> |
| <a href="/docs/geode-native/cpp/113/about-client-users-guide.html">Apache Geode Native Documentation</a> |
| </li> |
| <li class="has_submenu"> |
| <a href="/docs/geode-native/cpp/113/getting-started/getting-started-nc-client.html">Getting Started with the Native Library</a> |
| <ul> |
| <li> |
| <a href="/docs/geode-native/cpp/113/getting-started/getting-started-nc-client.html#set_up_dev_environment">Set Up Your Development Environment</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/getting-started/getting-started-nc-client.html#establish_cluster_access">Establish Access to a Geode Cluster</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/getting-started/getting-started-nc-client.html#app_dev_walkthroughs">Application Development Walkthroughs</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/getting-started/getting-started-nc-client.html#programming_examples">Programming Examples</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/getting-started/put-get-example.html">Put/Get/Remove Examples</a> |
| </li> |
| </ul> |
| </li> |
| <li class="has_submenu"> |
| <a href="/docs/geode-native/cpp/113/configuring/configuration.html">Configuring a Client Application</a> |
| <ul> |
| <li> |
| <a href="/docs/geode-native/cpp/113/configuring/system-level-configuration.html">System Level Configuration</a> |
| </li> |
| </ul> |
| </li> |
| |
| <li> |
| <a href="/docs/geode-native/cpp/113/configuring/config-client-cache.html">Configuring the Client Cache</a> |
| </li> |
| <li class="has_submenu"> |
| <a href="/docs/geode-native/cpp/113/regions/regions.html">Configuring Regions</a> |
| <ul> |
| <li> |
| <a href="/docs/geode-native/cpp/113/regions/registering-interest-for-entries.html">Registering Interest for Entries</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/regions/region-attributes.html">Region Attributes</a> |
| </li> |
| </ul> |
| </li> |
| |
| <li class="has_submenu"> |
| <a href="/docs/geode-native/cpp/113/connection-pools/configuring-pools.html">Configuring Pools</a> |
| <ul> |
| <li> |
| <a href="/docs/geode-native/cpp/113/connection-pools/client-pool-api.html">Native Client Pool API</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/connection-pools/configuring-pools-attributes-example.html">Pool Configuration Example and Settings</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/connection-pools/subscription-properties.html">Subscription Properties</a> |
| </li> |
| </ul> |
| </li> |
| |
| <li> |
| <a href="/docs/geode-native/cpp/113/serialization/data-serialization.html">Serializing Data</a> |
| </li> |
| |
| <li> |
| <a href="/docs/geode-native/cpp/113/remote-queries.html">Remote Queries</a> |
| </li> |
| |
| <li> |
| <a href="/docs/geode-native/cpp/113/continuous-queries.html">Continuous Queries</a> |
| </li> |
| |
| <li class="has_submenu"> |
| <a href="/docs/geode-native/cpp/113/security/security.html">Security: Authentication and Encryption</a> |
| <ul> |
| <li> |
| <a href="/docs/geode-native/cpp/113/security/authentication.html">Authentication</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/security/sslclientserver.html">TLS/SSL Client-Server Communication Encryption</a> |
| </li> |
| </ul> |
| </li> |
| |
| <li> |
| <a href="/docs/geode-native/cpp/113/function-execution.html">Function Execution</a> |
| </li> |
| |
| <li> |
| <a href="/docs/geode-native/cpp/113/transactions.html">Transactions</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/configuring/sysprops.html">System Properties</a> |
| </li> |
| <li> |
| <a href="/docs/geode-native/cpp/113/client-cache-ref.html">Client Cache XML Reference</a> |
| </li> |
| </ul> |
| </div> |
| </div> |
| |
| <!--googleon: index--> |
| |
| <main class="content content-layout" id="js-content" role="main"> |
| <a id="top"></a> |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <span style="font-weight:200;font-size:31px;" style="float:left;"> |
| <img src="/images/Apache_Geode_logo_symbol.png" style="height:26px;"> |
| Apache Geode Native C++ |
| </span> |
| <span class="local-header version-info" style="float:right;"> |
| <a href="https://cwiki.apache.org/confluence/display/GEODE/Release+Notes">CHANGELOG</a> |
| </span> |
| |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <h1 class="title-container" > |
| Remote Queries |
| </h1> |
| |
| <div id="js-quick-links" > |
| <div class="quick-links"><ul> |
| <li> |
| <a href="#RemoteQueryBasics">Remote Query Basics</a><ul> |
| <li><a href="#QueryLanguage">Query language: OQL</a></li> |
| <li><a href="#CreatingIndexes">Creating Indexes</a></li> |
| </ul> |
| </li> |
| <li> |
| <a href="#RemoteQueryAPI">Remote Query API</a><ul> |
| <li><a href="#Query">Query</a></li> |
| <li><a href="#ExecutingAQuery">Executing a Query from the Client</a></li> |
| <li><a href="#CppQueryExample">C++ Query Example</a></li> |
| </ul> |
| </li> |
| </ul></div> |
| </div> |
| <div class="to-top" id="js-to-top"> |
| <a href="#top" title="back to top"></a> |
| </div> |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| |
| <p>Use the remote query API to query your cached data stored on a cache server. </p> |
| |
| <h2 id="remote-query-basics"><a id="RemoteQueryBasics"></a>Remote Query Basics</h2> |
| |
| <p>Queries are evaluated and executed on the cache server, and the results are returned to the client. |
| You can optimize your queries by defining indexes on the cache server.</p> |
| |
| <p>Querying and indexing operate only on remote cache server contents.</p> |
| |
| <h3 id="query-language:-oql"><a id="QueryLanguage"></a>Query language: OQL</h3> |
| |
| <p>Geode provides a SQL-like querying language called OQL that allows you to access data stored in Geode regions. |
| OQL is very similar to SQL, but OQL allows you to query complex objects, object attributes, and methods.</p> |
| |
| <p>In the context of a query, specify the name of a region by its full path, starting with a slash (<code>/</code>).</p> |
| |
| <p>The query language supports drilling down into nested object structures. |
| Nested data collections can be explicitly referenced in the FROM clause of a query.</p> |
| |
| <p>A query execution returns its results as either a <code>ResultSet</code> or a <code>StructSet</code>. </p> |
| |
| <p>Query language features and grammar are described in the Geode manual at |
| <a href="geodeman/developing/querying_basics/chapter_overview.html">Querying</a>.</p> |
| |
| <h3 id="creating-indexes"><a id="CreatingIndexes"></a>Creating Indexes</h3> |
| |
| <p>Indexes can provide significant performance gains for query execution. You create and maintain indexes on the cache server. |
| For detailed information about working with indexes configured on a cache server, |
| see <a href="geodeman/developing/query_index/query_index.html">Working with Indexes</a> in the server’s documentation.</p> |
| |
| <h2 id="remote-query-api"><a id="RemoteQueryAPI"></a>Remote Query API</h2> |
| |
| <p>This section gives a general overview of the interfaces and classes that are provided by the query package API.</p> |
| |
| <h3 id="query"><a id="Query"></a>Query</h3> |
| |
| <p>You must create a <code>Query</code> object for each new query. The <code>Query</code> interface provides methods for |
| managing the compilation and execution of queries, and for retrieving an existing query string.</p> |
| |
| <p>A <code>Query</code> is obtained from a <code>QueryService</code>, which is obtained from one of two sources:</p> |
| |
| <ul> |
| <li><p>To create a <code>Query</code> that operates on the Geode server, use <code>apache::geode::client::Pool::getQueryService()</code> to instantiate a <code>QueryService</code> obtained from a <code>Pool</code>.</p></li> |
| <li><p>To create a <code>Query</code> that operates on your application’s local cache, use <code>apache::geode::client::Cache::getQueryService()</code> to instantiate a <code>QueryService</code> obtained from a <code>Cache</code>.</p></li> |
| </ul> |
| |
| <h3 id="executing-a-query-from-the-client"><a id="ExecutingAQuery"></a>Executing a Query from the Client</h3> |
| |
| <p>The essential steps to create and execute a query are:</p> |
| |
| <ol> |
| <li> Create an instance of the <code>QueryService</code> class. If you are using the pool API (recommended), you should obtain the <code>QueryService</code> from the pool.</li> |
| <li> Create a <code>Query</code> instance that is compatible with the OQL specification.</li> |
| <li> Use the <code>Query.execute()</code> method to submit the query string to the cache server. The server |
| remotely evaluates the query string and returns the results to the client.</li> |
| <li> Iterate through the returned objects.</li> |
| </ol> |
| |
| <h3 id="c++-query-example"><a id="CppQueryExample"></a>C++ Query Example</h3> |
| |
| <p>These C++ code excerpts are from the <code>examples/cpp/remotequery</code> example included in your client |
| distribution. See the example for full context.</p> |
| |
| <p>Following the steps listed above,</p> |
| |
| <ol> |
| <li><p>Obtain a <code>QueryService</code> object from the connection pool:</p> |
| <pre class="highlight plaintext"><code>std::shared_ptr<QueryService> queryService = nullptr; |
| queryService = pool->getQueryService(); |
| </code></pre></li> |
| <li><p>Create a <code>Query</code> object by calling <code>QueryService.newQuery()</code>, specifying your OQL query as a string parameter:</p> |
| <pre class="highlight plaintext"><code>auto query = queryService->newQuery("SELECT * FROM /custom_orders WHERE quantity > 30"); |
| </code></pre></li> |
| <li><p>Execute the query. Collect the query output, returned as either a <code>ResultSet</code> or a <code>StructSet</code>, and iterate through the results:</p> |
| <pre class="highlight plaintext"><code>auto queryResults = query->execute(); |
| |
| for (auto&& value : *queryResults) { |
| auto&& order = std::dynamic_pointer_cast<Order>(value); |
| std::cout << order->toString() << std::endl; |
| } |
| </code></pre></li> |
| </ol> |
| |
| |
| |
| </main> |
| </div> |
| </div> |
| </div> |
| |
| <div id="scrim"></div> |
| |
| <div class="container"> |
| <footer class="site-footer-links"> |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <div class="copyright"> |
| <a href='/'>Apache Geode Documentation</a> |
| © 2020 <a href='http://www.apache.org/'>The Apache Software Foundation</a>. |
| </div> |
| <div class="support"> |
| Need help? <a href="http://geode.apache.org/community" target="_blank">Visit the Community</a> |
| </div> |
| |
| </footer> |
| </div><!--end of container--> |
| |
| </body> |
| </html> |
