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The main content of this article is to explain the data model of HBase. Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Next let the editor to take you to learn "HBase data model explanation" it!

1 、 ROW KEY

Determine a row of data

Sorted in dictionary order.

Row key can only store 64k bytes of data.

2. Column Family column family & qualifier column

Each column in the HBase table belongs to a column family that must be given in advance as part of the table schema (schema) definition.

Column names are prefixed with column families, and each "column family" can have multiple column members (column); for example, course:math, course:english, new columns can be added on demand and dynamically; access control, storage, and tuning are all carried out at the column family level.

HBase stores the data in the same column of families in the same directory and is saved by several files.

3. Cell cell

Determined by the intersection of row and column coordinates; cells are versioned

The contents of the cell are unparsed byte arrays

The unit uniquely determined by {row key, column (= +), version}. The data in cell is typeless and is all stored in bytecode form.

4. Timestamp timestamp

In HBase, each cell storage unit has multiple versions of the same data, and the differences between each version are distinguished according to a unique time stamp. Different versions of data are sorted in reverse order in time, and the latest data version is ranked first.

The type of timestamp is 64-bit integer.

The timestamp can be assigned by HBase (automatically when the data is written), where the timestamp is the current system time accurate to milliseconds. Timestamps can also be explicitly assigned by the client, and if the application wants to avoid data version conflicts, it must generate its own unique timestamps.

Storage instance:

At this point, I believe you have a deeper understanding of "HBase's data model explanation". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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