HBase Data Model
The HBase Data Model is designed to handle semi-structured data that may differ in field size, which is a form of data and columns. The data model’s layout partitions the data into simpler components and spread them across the cluster. HBase's Data Model consists of various logical components, such as a table, line, column, family, column, column, cell, and edition.
An HBase table is made up of several columns. The tables in HBase defines upfront during the time of the schema specification.
An HBase row consists of a row key and one or more associated value columns. Row keys are the bytes that are not interpreted. Rows are ordered lexicographically, with the first row appearing in a table in the lowest order. The layout of the row key is very critical for this purpose.
A column in HBase consists of a family of columns and a qualifier of columns, which is identified by a character: (colon).
Apache HBase columns are separated into the families of columns. The column families physically position a group of columns and their values to increase its performance. Every row in a table has a similar family of columns, but there may not be anything in a given family of columns.
The same prefix is granted to all column members of a column family. For example, Column courses: history and courses: math, are both members of the column family of courses. The character of the colon (:) distinguishes the family of columns from the qualifier of the family of columns. The prefix of the column family must be made up of printable characters.
During schema definition time, column families must be declared upfront while columns are not specified during schema time. They can be conjured on the fly when the table is up and running. Physically, all members of the column family are stored on the file system together.
The column qualifier is added to a column family. A column standard could be content (html and pdf), which provides the content of a column unit. Although column families are set up at table formation, column qualifiers are mutable and can vary significantly from row to row.
A Cell store data and is quite a unique combination of row key, Column Family, and the Column. The data stored in a cell call its value and data types, which is every time treated as a byte.
In addition to each value, the timestamp is written and is the identifier for a given version of a number. The timestamp reflects the time when the data is written on the Region Server. But when we put data into the cell, we can assign a different timestamp value.