MSSQL实现复杂数据结构树的生成（mssql 生成树）

In a database system, data structure tree is the most efficient and most used way to store data. With the development of MSSQL, it has become a must-have tool for storing and manipulating data with tree-like structure. In this article, I will explain how to use MSSQL to generate complex data structure trees.

First of all, we need to create a database with some basic table structure. We need to create a main table with a unique identifier that can be used to track the relationships between the main table and the other tables. For example, if we want to create a table to index information related to members of a certain organization, then the main table can be named “members”, which will have fields like “name”, “title” and “identifier”.

Then, we need to use MSSQL to create a stored procedure for the tree handling. The stored procedure will need to read data from the main table and store it into the other tables. The stored procedure will also need to contain logic to build the tree structure from the main table. Generally, we can use a loop to traverse through the table, and create nodes for branches in the tree.

We also need to use MSSQL to create a function for the data retrieval. The function will be responsible for reading the tree structure from the database, and returning the results in a specific format. Depending on the type of data being stored, the results can be either an array or a dictionary.

With all this setup, the data structure tree can be generated and manipulated with MSSQL commands. To add new nodes to the tree, we can use the “insert” command, while to delete nodes we can use the “delete” command. The data retrieval function can also be used to access specific nodes in the tree, or even to traverse through the entire tree.

In conclusion, MSSQL is a powerful and versatile database that can be used to efficiently create and manipulate complex data structure trees. By creating the appropriate database tables, stored procedures and data retrieval functions, we can easily generate and modify tree-like data structures with ease.

“`sql

–Create the main table

CREATE TABLE members (

id int primary key,

name varchar(255),

title varchar(255),

identifier int

);

–Create stored procedure for tree handling

–Loop through the table and create nodes for branches

CREATE PROCEDURE BuildTree()

BEGIN

DECLARE @NodeValue int;

DECLARE @ParentID int;

DECLARE my_cursor CURSOR FOR

SELECT NodeValue, ParentID FROM members;

OPEN my_cursor;

FETCH NEXT FROM my_cursor INTO @NodeValue, @ParentID;

WHILE @@FETCH_STATUS = 0

BEGIN

IF @ParentID IS NULL

BEGIN

INSERT INTO members (NodeValue, ParentID)

VALUES (@NodeValue, @ParentID);

END

FETCH NEXT FROM my_cursor INTO @NodeValue, @ParentID;

END;

CLOSE my_cursor;

DEALLOCATE my_cursor;

END;

–Create a function to retrieve data

CREATE FUNCTION GetTreeData()

RETURNS TABLE

AS

RETURN

(

SELECT

m1.NodeValue, m1.ParentID, m2.NodeValue As ParentNodeValue

FROM

members m1

LEFT JOIN

members m2

ON m1.ParentID = m2.id

);