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Commit e26d1a82 authored by Goik Martin's avatar Goik Martin
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Completing query exercise

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......@@ -23,25 +23,21 @@
<qandadiv>
<qandaentry>
<question>
<para>This exercise aims at getting acquainted with basic <xref
linkend="glo_MongoDB"/> create, read, update and delete tasks
based on using the command line interface.</para>
<para>This exercise set aims at getting acquainted with basic
<xref linkend="glo_MongoDB"/> <code>create</code>,
<code>read</code>, <code>update</code> and <code>delete</code>
operations using the command line interface.</para>
<orderedlist>
<listitem>
<para>Follow <uri
xlink:href="https://docs.mongodb.com/getting-started/shell/introduction">https://docs.mongodb.com/getting-started/shell/introduction</uri>
(skipping the already completed installation section)
populating your database with multiple lecture entries
like:</para>
<para>Follow <uri
xlink:href="https://docs.mongodb.com/getting-started/shell/introduction">https://docs.mongodb.com/getting-started/shell/introduction</uri>
(skipping the already completed installation section) populating
your database with multiple lecture entries like:</para>
<programlisting language="json">{
<programlisting language="json">{
"title" : "Software development 1",
"studyCourse" : "MIB",
"programme" : "Bachelor",
"recommendedSemesters" : {
"semester" : [1, 2]
},
"recommendedSemesters" : [1, 2],
"lecture_id" : 113105
}
......@@ -50,9 +46,7 @@
"prerequisites" : [113105, 113102],
"studyCourse" : "MIB",
"programme" : "Bachelor",
"recommendedSemesters" : {
"semester" : [2, 3, 4]
},
"recommendedSemesters" : [2, 3, 4],
"lecture_id" : 113213
}
......@@ -60,85 +54,30 @@
"title" : "Object Recognition in Image and Video Data",
"studyCourse" : "CSM",
"programme" : "Master",
"recommendedSemesters" : {
"semester" : [1, 2, 3]
},
"recommendedSemesters" : [1, 2, 3],
"lecture_id" : 143108
}</programlisting>
</listitem>
<listitem xml:id="sda1ItemMongoDefineIndex">
<para>Define a <link
xlink:href="https://docs.mongodb.com/manual/core/index-unique">unique
index</link> on the <property>lecture_id</property> property
and check whether the MongoDB Server rejects an attempt
inserting a duplicate key value.</para>
</listitem>
<listitem>
<para>List all index definitions.</para>
</listitem>
<listitem>
<para>Taking a glimpse at <link
xlink:href="https://docs.mongodb.com/getting-started/shell/query">Find
or Query Data with the mongo Shell</link> and craft the
following queries:</para>
<orderedlist>
<listitem>
<para>All lectures.</para>
</listitem>
<listitem>
<para>The (unique) lecture having
<property>lecture_id</property>=113213.</para>
</listitem>
<listitem>
<para>All lectures belonging to a <quote>Master</quote>
programme.</para>
</listitem>
<listitem>
<para>All lectures being recommended for semester
4.</para>
</listitem>
<listitem>
<para>All lectures</para>
</listitem>
</orderedlist>
</listitem>
<listitem>
<para>Drop your index definition from step <xref
linkend="sda1ItemMongoDefineIndex"/>.</para>
</listitem>
</orderedlist>
</question>
<answer>
<orderedlist>
<listitem>
<para>Database server acknowledgement <coref
linkend="sda1ProgMongoInsertAck"/> upon insertion of three
lectures <coref linkend="sda1ProgMongoInsertS1"/>, <coref
linkend="sda1ProgMongoInsertS2"/> and <coref
linkend="sda1ProgMongoInsertS1"/> :</para>
<para>Database server acknowledgement <coref
linkend="sda1ProgMongoInsertAck"/> upon successful insertion
<coref linkend="sda1ProgMongoInsertS1"/>, <coref
linkend="sda1ProgMongoInsertS2"/> and <coref
linkend="sda1ProgMongoInsertS1"/> of three lectures :</para>
<programlisting language="json">db.university.insertMany(
<programlisting language="json">db.university.insert(
[
{
"title" : "Software development 1",
"studyCourse" : "MIB",
"programme" : "Bachelor",
"recommendedSemesters" : {
"semester" : [1, 2]
},
"recommendedSemesters" : [1, 2],
"lecture_id" : 113105
}, {...
}
}, {
"title" : "Software development 2",
...
}, ...
]);
{
......@@ -149,15 +88,22 @@
ObjectId("586942cb27e04cf209347689") <co xml:id="sda1ProgMongoInsertS3"/>
]
}</programlisting>
</listitem>
</answer>
</qandaentry>
</qandadiv>
<listitem>
<para>Defining a <link
xlink:href="https://docs.mongodb.com/manual/core/index-unique">unique
index</link> on the <property>lecture_id</property>
property:</para>
<qandadiv xml:id="sda1ItemMongoDefineIndex">
<qandaentry>
<question>
<para>Define a <link
xlink:href="https://docs.mongodb.com/manual/core/index-unique">unique
index</link> on the <property>lecture_id</property> property and
check whether the MongoDB Server rejects a duplicate key
insertion attempt.</para>
</question>
<programlisting language="json">&gt; db.university.createIndex( { "lecture_id": 1 }, { unique: true } )
<answer>
<programlisting language="json">&gt; db.university.createIndex( { "lecture_id": 1 }, { unique: true } )
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
......@@ -165,30 +111,51 @@
"ok" : 1
}</programlisting>
<para>Now a duplicate key value insert attempt gets flagged
as an error:</para>
<para>Now a duplicate key value insert attempt gets flagged as
an error:</para>
<programlisting language="json">db.university.insert({
<programlisting language="json">db.university.insert({
"title" : "Object Recognition in Image and Video Data",
...
"lecture_id" : 143108 })
WriteResult({
"nInserted" : 0,
"writeError" : {
"<emphasis role="bold">writeError" : {
"code" : 11000,
"errmsg" : "E11000 duplicate key error collection: test.university index:
lecture_id_1 dup key: { : 143108.0 }"
lecture_id_1 dup key: { : 143108.0 }"</emphasis>
}
})</programlisting>
</listitem>
</answer>
</qandaentry>
</qandadiv>
<listitem>
<para>Obtaining a list of all index definitions:</para>
<qandadiv>
<qandaentry>
<question>
<para>List all index definitions. Explain the result.</para>
</question>
<programlisting language="json">&gt; db.university.getIndexes()
<answer>
<para>Our collection contains two index definitions:</para>
<calloutlist>
<callout arearefs="sda1CalloutMongoListIndexes-1-co"
xml:id="sda1CalloutMongoListIndexes-1">
<para>First index on MogoDB auto generated attribute.</para>
</callout>
<callout arearefs="sda1CalloutMongoListIndexes-2-co"
xml:id="sda1CalloutMongoListIndexes-2">
<para>Custom unique index definition resulting from previous
step.</para>
</callout>
</calloutlist>
<programlisting language="json">&gt; db.university.getIndexes()
[
{ <co linkends="sda1CalloutMongoListIndexes-1"
xml:id="sda1CalloutMongoListIndexes-1-co"/>
xml:id="sda1CalloutMongoListIndexes-1-co"/>
"v" : 2,
"key" : {
"_id" : 1
......@@ -197,7 +164,7 @@ WriteResult({
"ns" : "test.university"
},
{ <co linkends="sda1CalloutMongoListIndexes-2"
xml:id="sda1CalloutMongoListIndexes-2-co"/>
xml:id="sda1CalloutMongoListIndexes-2-co"/>
"v" : 2,
"unique" : true,
"key" : {
......@@ -206,62 +173,144 @@ WriteResult({
"name" : "lecture_id_1",
"ns" : "test.university"
}
]
&gt;</programlisting>
<calloutlist>
<callout arearefs="sda1CalloutMongoListIndexes-1-co"
xml:id="sda1CalloutMongoListIndexes-1">
<para>First index being automatically generated by
MogoDB.</para>
</callout>
<callout arearefs="sda1CalloutMongoListIndexes-2-co"
xml:id="sda1CalloutMongoListIndexes-2">
<para>Custom key definition from previous step.</para>
</callout>
</calloutlist>
]</programlisting>
</answer>
</qandaentry>
</qandadiv>
<qandadiv>
<qandaentry>
<question>
<para>Take a glimpse at <link
xlink:href="https://docs.mongodb.com/getting-started/shell/query">Find
or Query Data with the mongo Shell</link> and craft the
following queries:</para>
<orderedlist>
<listitem>
<para>All lectures.</para>
</listitem>
<listitem>
<para>Taking a glimpse at <link
xlink:href="https://docs.mongodb.com/getting-started/shell/query">Find
or Query Data with the mongo Shell</link> and craft the
following queries:</para>
<orderedlist>
<listitem>
<para>All lectures.</para>
</listitem>
<listitem>
<para>The (unique) lecture having
<property>lecture_id</property>=113213.</para>
</listitem>
<listitem>
<para>All lectures belonging to a <quote>Master</quote>
programme.</para>
</listitem>
<listitem>
<para>All lectures being recommended for semester
4.</para>
</listitem>
<listitem>
<para>All lectures</para>
</listitem>
</orderedlist>
<para>The (unique) lecture having
<property>lecture_id</property>=113213.</para>
</listitem>
<listitem>
<para>Dropping a custom index:</para>
<para>The <property>title</property> values of all lectures
belonging to a <quote>Bachelor</quote> programme suppressing
the auto generated <property>_id</property> property</para>
</listitem>
<programlisting language="json">&gt; db.university.dropIndex( { "lecture_id": 1 } )
{ "nIndexesWas" : 2, "ok" : 1 }</programlisting>
<listitem>
<para>All lectures being recommended for semester 3.</para>
</listitem>
</orderedlist>
</question>
<answer>
<glosslist>
<glossentry>
<glossterm>All lectures.</glossterm>
<glossdef>
<para>Querying all objects of given collection:</para>
<programlisting language="json">&gt; db.university.find()
{ "_id" : ObjectId("586a230651557f1957460a37"), "title" : "Software development 1", ..., "lecture_id" : 113105 }
{ "_id" : ObjectId("586a230651557f1957460a38"), "title" : "Software development 2", ..., "lecture_id" : 113213 }
{ "_id" : ObjectId("586a230651557f1957460a39"), "title" : "Object Recognition ...", ..., "lecture_id" : 143108 }</programlisting>
</glossdef>
</glossentry>
<glossentry>
<glossterm>The (unique) lecture having
<property>lecture_id</property>=113213.</glossterm>
<glossdef>
<programlisting language="json">db.university.find({lecture_id : 143108})
{
"_id" : ObjectId("586a230651557f1957460a39"),
"title" : "Object Recognition in Image and Video Data",
...
<emphasis role="bold">"lecture_id" : 143108</emphasis>}</programlisting>
</glossdef>
</glossentry>
<glossentry>
<glossterm>The <property>title</property> values of all
lectures belonging to a <quote>Bachelor</quote> programme
suppressing the auto generated _id property</glossterm>
<glossdef>
<programlisting language="json">db.university.find({programme : "Bachelor"}, {title: 1, _id: 0})
{ "title" : "Software development 1" }
{ "title" : "Software development 2" }</programlisting>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Properties <property>title</property> and
<property>recommendedSemesters</property> of all lectures
being recommended for semester 3</glossterm>
<glossdef>
<programlisting language="json">db.university.find({recommendedSemesters: 3}, {title:1, recommendedSemesters:1, _id:0})
{ "title" : "Software development 2", "recommendedSemesters" : [ 2, 3, 4 ] }
{ "title" : "Object Recognition in Image and Video Data", "recommendedSemesters" : [ 1, 2, 3 ] }</programlisting>
</glossdef>
</glossentry>
</glosslist>
</answer>
</qandaentry>
<qandaentry>
<question>
<para>Drop all your collection's data records. Will your
database be completely in its previous state?</para>
</question>
<answer>
<programlisting language="json">db.university.remove({});
WriteResult({ "nRemoved" : 3 })</programlisting>
<para>We identify three deleted records corresponding to our
initial inserts. The index definitions however remain:</para>
<programlisting language="json">&gt; db.university.getIndexes()
[
{
"v" : 2,
"key" : {
"_id" : 1
},
"name" : "_id_",
"ns" : "test.university"
},
{
"v" : 2,
"unique" : true,
"key" : {
"lecture_id" : 1
},
"name" : "lecture_id_1",
"ns" : "test.university"
}
]</programlisting>
</answer>
</qandaentry>
</qandadiv>
<qandadiv>
<qandaentry>
<question>
<para>Drop the remaining custom index definition from step <xref
linkend="sda1ItemMongoDefineIndex"/>.</para>
</question>
<answer>
<programlisting language="json">&gt; db.university.dropIndex( { "lecture_id": 1 } )
{ "nIndexesWas" : 2, "ok" : 1 }</programlisting>
</answer>
</qandaentry>
</qandadiv>
......
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