HBase: HBase data model

hbase storage column is, one row includes a row key, each row has a time stamp representative of a plurality of different versions, a plurality of column group, each column group has a plurality of columns, each column can store a plurality of data

Row Key

• Decided row of data
• According to the dictionary sort order
• Row Key only 64K bytes of storage

Column Family column family & qualifier column

• Each column of the table HBase column belongs to a group, the group must be given in advance a portion of the column (schema) as defined in the table mode. Such ascreate 'test', 'course'
• Column column name as a prefix family, each "column group" members can have a plurality of columns (column); such as: course:math，course:englishnew family members column (columns) can subsequently needed, dynamically join;
• Access control, storage and tuning are carried out in the column inside Group
• HBase the same column family which data is stored in the same directory, saving several files.

Timestamp timestamp

• HBase each memory cell in the cell there are multiple versions of the same data, to distinguish the differences between each version of the time stamp based on a unique, different versions of data in a time reverse order, the latest version of the data at the top
• Type of stamp is 64-bit integer.
• Timestamp may (automatically writing data) assigned by HBase, this time stamp is accurate to the current system time in milliseconds.
• Time stamp can also be explicitly assigned by the client, if the application data to avoid version conflicts, it must generate their own unique stamp.