Database Reference
In-Depth Information
Concepts
In this section, we provide a quick overview of core HBase concepts. At a minimum, a
passing familiarity will ease the digestion of all that follows.
Whirlwind Tour of the Data Model
Applications store data in labeled tables. Tables are made of rows and columns. Table cells
— the intersection of row and column coordinates — are versioned. By default, their ver-
sion is a timestamp auto-assigned by HBase at the time of cell insertion. A cell's content is
an uninterpreted array of bytes. An example HBase table for storing photos is shown in
Figure 20-1. The HBase data model, illustrated for a table storing photos
Table row keys are also byte arrays, so theoretically anything can serve as a row key, from
strings to binary representations of long or even serialized data structures. Table rows are
sorted by row key, aka the table's primary key. The sort is byte-ordered. All table accesses
are via the primary key.
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