Changes between Version 1 and Version 2 of waue/2009/0626

Timestamp:

Jun 26, 2009, 3:21:44 PM (16 years ago)

Author:

waue

Comment:

--

waue/2009/0626

@@ +1 @@
+= 新 hbase 解析 =
+ * hbase 已經到0.19.3了，可惜的是 hbase 0.18.1的api及文件都已經從官方網頁被拿掉了，所幸hbase 0.18 與hbase 0.19相差無幾
+ * hbase 0.1.3 到 hbase 0.19.3 中間好像已經包含了十幾代，但是其實類似java 1.4 直接跳躍 到 java 5 一樣，hbase 0.1.3 -> hbase 0.2.x -> hbase 0.18.x -> hbase 0.19.x 
+   * 從 hbase 0.18.x 之後，其版本名稱就直接對應hadoop 的版本名稱，如 hbase 0.18 搭配 hadoop 0.18 ， hbase 0.19 搭配hadoop 0.19
+ * 筆者開發hbase時是 hbase 0.13的時代，現在又重拾舊業，發現已經差很多了。如
+ * 找資料：
+   * hbase 0.13 : select * from 'table_name'
+   * hbase 0.19 : scan 'table_name'
+ * 資料庫結構：
+   * hbase 0.13 :
+|| || column_family:column_quolify1|| column_family:column_quolify2|| column_family:column_quolify3||
+|| time stamp 2 || cell_value1 || cell_value2|| cell_value3||
+|| time stamp 1 || cell_value1 || cell_value2|| cell_value3||
+   * hbase 0.19 : 加入 row 這個結構
+
+
+
+{{{
+#!java
+
+                HBaseConfiguration config = new HBaseConfiguration();
+}}}
+
+{{{
+#!java
+                HBaseAdmin admin = new HBaseAdmin(config);
+                if (!admin.tableExists(table_name)) {
+                        System.out.println("HTable : " + table_name
+                                        + "  creating ... please wait");
+                        HTableDescriptor tableDesc = new HTableDescriptor(table_name);
+                        // add column family
+                        tableDesc.addFamily(new HColumnDescriptor(colomn_family));
+                        admin.createTable(tableDesc);
+                }
+}}}
+
+{{{
+#!java
+
+                
+                BatchUpdate batchUpdate = new BatchUpdate(hbase_row);
+                batchUpdate.put(colomn_family+column_quolify, Bytes.toBytes(value));
+                batchUpdate.delete(colomn_family+"cellIWantDeleted");
+}}}
+
+{{{
+#!java
+                HTable table = new HTable(config, table_name);
+                table.commit(batchUpdate);
+}}}
+
+{{{
+#!java
+
+                Cell cell = table.get(hbase_row, colomn_family+column_quolify);
+                System.out.print(cell.getValue());
+
+}}}
+
+{{{
+#!java
+                Scanner scanner =
+                table.getScanner(new String[] { colomn_family+column_quolify });
+
+                RowResult rowResult = scanner.next();
+
+                while (rowResult != null) {
+
+                        System.out.println("Found row: "
+                                        + Bytes.toString(rowResult.getRow())
+                                        + " with value: "
+                                        + rowResult.get(Bytes
+                                                        .toBytes(colomn_family+column_quolify)));
+                        rowResult = scanner.next();
+                }
+
+                for (RowResult result : scanner) {
+                        System.out.println("Found row: "
+                                        + Bytes.toString(rowResult.getRow())
+                                        + " with value: "
+                                        + rowResult.get(Bytes
+                                                        .toBytes(colomn_family+column_quolify)));
+                }
+
+                scanner.close();
+
+
+
+}}}
+
+
+ * 完整程式碼如下
+
 {{{
 #!java