Index: src/docbkx/book.xml
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--- src/docbkx/book.xml (revision 1087323)
+++ src/docbkx/book.xml (working copy)
@@ -315,6 +315,69 @@
via the table row key -- its primary key.
+ Conceptual View
+
+ The following example is a slightly modified form of the one on page 2 of the BigTable paper.
+ There is a table called "webtable" that contains two ColumnFamilies named "contents:" and "anchor:". In this example, "anchor:" contains two columns (cssnsi.com, my.look.ca) and "contents:" contains one column (html).
+
+
+
+ Physical View
+
+ Although at a conceptual level tables may be viewed as a sparse set of rows, physically they are stored on a per-ColumnFamily basis. New columns (i.e., "columnfamily:column") can be added to any ColumnFamily without pre-announcing them.
+
+It is important to note in the diagram above that the empty cells shown in the conceptual view are not stored since they need not be in a column-oriented storage format. Thus a request for the value of the "contents:html" column at time stamp t8 would return no value. Similarly, a request for an "anchor:my.look.ca" value at time stamp t9 would return no value.
+
+However, if no timestamp is supplied, the most recent value for a particular column would be returned and would also be the first one found since timestamps are stored in descending order. Thus a request for the values of all columns in the row "com.cnn.www" if no timestamp is specified would be: the value of "contents:html" from time stamp t6, the value of "anchor:cnnsi.com" from time stamp t9, the value of "anchor:my.look.ca" from time stamp t8.
+
+
+
+
Table