In-depth understanding of cloud storage and cloud computing-data models and implementation methods

Common data models include key/value and schema free (Free List mode,

Key/value. Each record consists of two fields. One is used as the primary key and the other is used to store the recorded data.

Schema free, each record has a primary key consisting of several columns, a bit similar to a relational database

Two methods are basically used to implement these models:Hash and add a linked list or B + tree

Hash and linked list: the storage location is determined by hashing the key. data with the same hash value is stored as a linked list.

B + tree: Features of B + tree

1. The number of keywords in a node is the same as that in bytes.

2. All leaf nodes contain all the keyword information and the pointer to the record.

3. Leaf nodes are connected in ascending order based on keywords

4. All non-leaf nodes can be regarded as index parts. The nodes only contain the maximum keywords in their Subtrees.

5 there are usually two head pointers on the B + tree, one pointing to the root node and the other pointing to the leaf node with the smallest keyword.