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<page id="mongoc-common-task-examples"
type="topic"
xmlns="http://projectmallard.org/1.0/">
<info>
<link type="guide" xref="index#basic-operations"/>
</info>
<title>Common Tasks</title>
<section id="common-tasks">
<p>Drivers for some other languages provide helper functions to perform certain common tasks. In the C Driver we must explicitly build commands to send to the server.</p>
<p>This snippet contains example code for the <code>explain</code>, <code>copydb</code> and <code>cloneCollection</code> commands.</p>
<section id="setup">
<title>Setup</title>
<p>First we'll write some code to insert sample data:</p>
<code mime="text/x-csrc"><include parse="text" href="../examples/doc-common-insert.c" xmlns="http://www.w3.org/2001/XInclude" /></code>
</section>
<section id="explain">
<title>"explain" Command</title>
<p>This is how to use the <code>explain</code> command in MongoDB 3.2+:</p>
<code mime="text/x-csrc"><include parse="text" href="../examples/common_operations/explain.c" xmlns="http://www.w3.org/2001/XInclude" /></code>
</section>
<section id="copydb">
<title>"copydb" Command</title>
<p>This example requires two instances of mongo to be running.</p>
<p>Here's how to use the <code>copydb</code> command to copy a database from another instance of MongoDB:</p>
<code mime="text/x-csrc"><include parse="text" href="../examples/common_operations/copydb.c" xmlns="http://www.w3.org/2001/XInclude" /></code>
</section>
<section id="clone-collection">
<title>"cloneCollection" Command</title>
<p>This example requires two instances of mongo to be running.</p>
<p>Here's an example of the <code>cloneCollection</code> command to clone a collection from another instance of MongoDB:</p>
<code mime="text/x-csrc"><include parse="text" href="../examples/common_operations/clone-collection.c" xmlns="http://www.w3.org/2001/XInclude" /></code>
</section>
<section id="main">
<title>Running</title>
<listing>
<title>examples/common-operations.c</title>
<code mime="text/x-csrc"><include parse="text" href="../examples/common_operations/common-operations.c" xmlns="http://www.w3.org/2001/XInclude" /></code>
</listing>
<p>First launch two separate instances of mongod (must be done from separate shells):</p>
<screen><output style="prompt">$ </output><input>mongod</input></screen>
<screen><output style="prompt">$ </output><input>mkdir /tmp/db2</input>
<output style="prompt">$ </output><input>mongod --dbpath /tmp/db2 --port 27018 # second instance</input></screen>
<p>Now compile and run the example program:</p>
<screen><output style="prompt">$ </output><input>cd examples/common_operations/</input>
<output style="prompt">$ </output><input>gcc -Wall -o example common-operations.c $(pkg-config --cflags --libs libmongoc-1.0)</input>
<output style="prompt">$ </output><input>./example localhost:27017 localhost:27018</input>
<output>
Inserting data
explain
{
"executionStats" : {
"allPlansExecution" : [],
"executionStages" : {
"advanced" : 19,
"direction" : "forward" ,
"docsExamined" : 76,
"executionTimeMillisEstimate" : 0,
"filter" : {
"x" : {
"$eq" : 1
}
},
"invalidates" : 0,
"isEOF" : 1,
"nReturned" : 19,
"needTime" : 58,
"needYield" : 0,
"restoreState" : 0,
"saveState" : 0,
"stage" : "COLLSCAN" ,
"works" : 78
},
"executionSuccess" : true,
"executionTimeMillis" : 0,
"nReturned" : 19,
"totalDocsExamined" : 76,
"totalKeysExamined" : 0
},
"ok" : 1,
"queryPlanner" : {
"indexFilterSet" : false,
"namespace" : "test.things",
"parsedQuery" : {
"x" : {
"$eq" : 1
}
},
"plannerVersion" : 1,
"rejectedPlans" : [],
"winningPlan" : {
"direction" : "forward" ,
"filter" : {
"x" : {
"$eq" : 1
}
},
"stage" : "COLLSCAN"
}
},
"serverInfo" : {
"gitVersion" : "05552b562c7a0b3143a729aaa0838e558dc49b25" ,
"host" : "MacBook-Pro-57.local",
"port" : 27017,
"version" : "3.2.6"
}
}
copydb
{ "ok" : 1 }
clone collection
{ "ok" : 1 }
</output>
</screen>
</section>
</section>
</page>
|
