HBASE-4267 book.xml - data model edits
git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1162621 13f79535-47bb-0310-9956-ffa450edef68
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Doug Meil
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7aa6268778
commit
4199e1ae02
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@ -635,6 +635,61 @@ admin.enableTable(table);
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specifies a <literal>cell</literal> in HBase.
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Cell content is uninterrpreted bytes</para>
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</section>
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<section xml:id="data_model_operations">
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<title>Data Model Operations</title>
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<para>The four primary data model operations are Get, Put, Scan, and Delete. Operations are applied via
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<link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/HTable.html">HTable</link> instances.
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</para>
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<section xml:id="get">
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<title>Get</title>
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<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Get.html">Get</link> returns
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attributes for a specified row. Gets are executed via
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<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">
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HTable.get</link>.
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</para>
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</section>
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<section xml:id="put">
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<title>Put</title>
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<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Put.html">Put</link> either
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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
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<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">
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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">
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HTable.batch</link> (non-writeBuffer).
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</para>
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</section>
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<section xml:id="scan">
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<title>Scans</title>
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<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Scan.html">Scan</link> allow
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iteration over multiple rows for specified attributes.
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</para>
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<para>The following is an example of a
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on an HTable table instance. Assume that a table is populated with rows with keys "row1", "row2", "row3",
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and then another set of rows with the keys "abc1", "abc2", and "abc3". The following example shows how startRow and stopRow
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can be applied to a Scan instance to return the rows beginning with "row".
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<programlisting>
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HTable htable = ... // instantiate HTable
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Scan scan = new Scan();
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scan.addColumn(Bytes.toBytes("cf"),Bytes.toBytes("attr"));
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scan.setStartRow( Bytes.toBytes("row"));
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scan.setStopRow( Bytes.toBytes("row" + new byte[] {0})); // note: stop key != start key
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for(Result result : htable.getScanner(scan)) {
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// process Result instance
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}
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</programlisting>
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</para>
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</section>
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<section xml:id="delete">
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<title>Delete</title>
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<para><link xlink:href="http://hbase.apache.org/docs/current/api/org/apache/hadoop/hbase/client/Delete.html">Delete</link> removes
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a row from a table. Deletes are executed via
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<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">
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HTable.delete</link>.
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</para>
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</section>
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</section>
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<section xml:id="versions">
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<title>Versions<indexterm><primary>Versions</primary></indexterm></title>
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@ -728,25 +783,26 @@ admin.enableTable(table);
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<section xml:id="default_get_example">
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<title>Default Get Example</title>
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<para>The following Get will only retrieve the current version of the row
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<programlisting>
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Get get = new Get(Bytes.toBytes("row1"));
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Result r = htable.get(get);
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byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value </programlisting>
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<programlisting>
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Get get = new Get(Bytes.toBytes("row1"));
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Result r = htable.get(get);
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byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value
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</programlisting>
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</para>
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</section>
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<section xml:id="versioned_get_example">
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<title>Versioned Get Example</title>
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<para>The following Get will return the last 3 versions of the row.
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<programlisting>
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Get get = new Get(Bytes.toBytes("row1"));
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get.setMaxVersions(3); // will return last 3 versions of row
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Result r = htable.get(get);
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byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value
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List<KeyValue> kv = r.getColumn(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns all versions of this column
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</programlisting>
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<programlisting>
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Get get = new Get(Bytes.toBytes("row1"));
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get.setMaxVersions(3); // will return last 3 versions of row
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Result r = htable.get(get);
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byte[] b = r.getValue(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns current version of value
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List<KeyValue> kv = r.getColumn(Bytes.toBytes("cf"), Bytes.toBytes("attr")); // returns all versions of this column
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</programlisting>
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</para>
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</section>
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<section>
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<title>Put</title>
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@ -763,24 +819,25 @@ admin.enableTable(table);
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<section xml:id="implicit_version_example">
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<title>Implicit Version Example</title>
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<para>The following Put will be implicitly versioned by HBase with the current time.
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<programlisting>
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Put put = new Put(Bytes.toBytes(row));
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put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), Bytes.toBytes( data));
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htable.put(put);
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</programlisting>
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<programlisting>
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Put put = new Put(Bytes.toBytes(row));
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put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), Bytes.toBytes( data));
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htable.put(put);
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</programlisting>
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</para>
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</section>
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<section xml:id="explicit_version_example">
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<title>Explicit Version Example</title>
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<para>The following Put has the version timestamp explicitly set.
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<programlisting>
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Put put = new Put( Bytes.toBytes(row ));
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long explicitTimeInMs = 555; // just an example
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put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), explicitTimeInMs, Bytes.toBytes(data));
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htable.put(put);
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</programlisting>
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<programlisting>
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Put put = new Put( Bytes.toBytes(row));
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long explicitTimeInMs = 555; // just an example
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put.add(Bytes.toBytes("cf"), Bytes.toBytes("attr1"), explicitTimeInMs, Bytes.toBytes(data));
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htable.put(put);
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</programlisting>
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</para>
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</section>
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</section>
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<section>
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