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HBASE-4267 book.xml - data model edits 

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1162621 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Doug Meil 2011-08-29 01:20:30 +00:00
parent 7aa6268778
commit 4199e1ae02
1 changed files with 80 additions and 23 deletions
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101
src/docbkx/book.xml
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@ -635,6 +635,61 @@ admin.enableTable(table);
specifies a <literal>cell</literal> in HBase. specifies a <literal>cell</literal> in HBase.
Cell content is uninterrpreted bytes</para> Cell content is uninterrpreted bytes</para>
</section> </section>
<section xml:id="data_model_operations">
<title>Data Model Operations</title>
<para>The four primary data model operations are Get, Put, Scan, and Delete. Operations are applied via
<link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/HTable.html">HTable</link> instances.
</para>
<section xml:id="get">
<title>Get</title>
<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Get.html">Get</link> returns
attributes for a specified row. Gets are executed via
<link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#get%28org.apache.hadoop.hbase.client.Get%29">
HTable.get</link>.
</para>
</section>
<section xml:id="put">
<title>Put</title>
<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Put.html">Put</link> either
adds new rows to a table (if the key is new) or can update existing rows (if the key already exists). Puts are executed via
<link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#put%28org.apache.hadoop.hbase.client.Put%29">
HTable.put</link> (writeBuffer) or <link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#batch%28java.util.List%29">
HTable.batch</link> (non-writeBuffer).
</para>
</section>
<section xml:id="scan">
<title>Scans</title>
<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Scan.html">Scan</link> allow
iteration over multiple rows for specified attributes.
</para>
<para>The following is an example of a
on an HTable table instance. Assume that a table is populated with rows with keys "row1", "row2", "row3",
and then another set of rows with the keys "abc1", "abc2", and "abc3". The following example shows how startRow and stopRow
can be applied to a Scan instance to return the rows beginning with "row".
<programlisting>
HTable htable = ... // instantiate HTable
Scan scan = new Scan();
scan.addColumn(Bytes.toBytes("cf"),Bytes.toBytes("attr"));
scan.setStartRow( Bytes.toBytes("row"));
scan.setStopRow( Bytes.toBytes("row" + new byte[] {0})); // note: stop key != start key
for(Result result : htable.getScanner(scan)) {
// process Result instance
}
</programlisting>
</para>
</section>
<section xml:id="delete">
<title>Delete</title>
<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Delete.html">Delete</link> removes
a row from a table. Deletes are executed via
<link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#delete%28org.apache.hadoop.hbase.client.Delete%29">
HTable.delete</link>.
</para>
</section>
</section>
<section xml:id="versions"> <section xml:id="versions">
<title>Versions<indexterm><primary>Versions</primary></indexterm></title> <title>Versions<indexterm><primary>Versions</primary></indexterm></title>
@ -728,22 +783,23 @@ admin.enableTable(table);
<section xml:id="default_get_example"> <section xml:id="default_get_example">
<title>Default Get Example</title> <title>Default Get Example</title>
<para>The following Get will only retrieve the current version of the row <para>The following Get will only retrieve the current version of the row
<programlisting> <programlisting>
Get get = new Get(Bytes.toBytes("row1")); Get get = new Get(Bytes.toBytes("row1"));
Result r = htable.get(get); Result r = htable.get(get);
byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value </programlisting> byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value
</programlisting>
</para> </para>
</section> </section>
<section xml:id="versioned_get_example"> <section xml:id="versioned_get_example">
<title>Versioned Get Example</title> <title>Versioned Get Example</title>
<para>The following Get will return the last 3 versions of the row. <para>The following Get will return the last 3 versions of the row.
<programlisting> <programlisting>
Get get = new Get(Bytes.toBytes("row1")); Get get = new Get(Bytes.toBytes("row1"));
get.setMaxVersions(3); // will return last 3 versions of row get.setMaxVersions(3); // will return last 3 versions of row
Result r = htable.get(get); Result r = htable.get(get);
byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value
List&lt;KeyValue&gt; kv = r.getColumn(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns all versions of this column List&lt;KeyValue&gt; kv = r.getColumn(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns all versions of this column
</programlisting> </programlisting>
</para> </para>
</section> </section>
@ -763,24 +819,25 @@ admin.enableTable(table);
<section xml:id="implicit_version_example"> <section xml:id="implicit_version_example">
<title>Implicit Version Example</title> <title>Implicit Version Example</title>
<para>The following Put will be implicitly versioned by HBase with the current time. <para>The following Put will be implicitly versioned by HBase with the current time.
<programlisting> <programlisting>
Put put = new Put(Bytes.toBytes(row)); Put put = new Put(Bytes.toBytes(row));
put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), Bytes.toBytes( data)); put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), Bytes.toBytes( data));
htable.put(put); htable.put(put);
</programlisting> </programlisting>
</para> </para>
</section> </section>
<section xml:id="explicit_version_example"> <section xml:id="explicit_version_example">
<title>Explicit Version Example</title> <title>Explicit Version Example</title>
<para>The following Put has the version timestamp explicitly set. <para>The following Put has the version timestamp explicitly set.
<programlisting> <programlisting>
Put put = new Put( Bytes.toBytes(row )); Put put = new Put( Bytes.toBytes(row));
long explicitTimeInMs = 555; // just an example long explicitTimeInMs = 555; // just an example
put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), explicitTimeInMs, Bytes.toBytes(data)); put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), explicitTimeInMs, Bytes.toBytes(data));
htable.put(put); htable.put(put);
</programlisting> </programlisting>
</para> </para>
</section> </section>
</section> </section>
<section> <section>