mysql存储过程递归调用产生树数据 使用finereport的树下拉框时,要求提供有层次结构的数据。例如:一级001,二级001001,三级001001001 等。而我们一般的递归表是这样的,定义一个id和一个pid,id和pid在长度上没有父子关系。这样的数据,finereport是不认的。
mysql存储过程递归调用产生树数据使用finereport的树下拉框时,要求提供有层次结构的数据。例如:一级001,二级001001,三级001001001 等。而我们一般的递归表是这样的,定义一个id和一个pid,id和pid在长度上没有父子关系。这样的数据,finereport是不认的。故只能通过存储过程进行转换。 代码如下: SET FOREIGN_KEY_CHECKS=0; -- ---------------------------- -- Table structure for `t_tlm_tree` -- ---------------------------- DROP TABLE IF EXISTS `t_tlm_tree`; CREATE TABLE `t_tlm_tree` ( `id` varchar(100) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL DEFAULT '0' , `pid` varchar(100) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL , `nodename` varchar(200) CHARACTER SET utf8 COLLATE utf8_unicode_ci NULL DEFAULT NULL , `fast` int(11) NULL DEFAULT NULL , PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARACTER SET=utf8 COLLATE=utf8_unicode_ci ; -- ---------------------------- -- Records of t_tlm_tree -- ---------------------------- BEGIN; INSERT INTO `t_tlm_tree` VALUES ('10000', '-1', '中国', '1'), ('10001', '10000', '浙江', '1'), ('10002', '10000', '河南', '1'), ('10003', '10001', '杭州', '1'), ('10004', '10001', '温州', '1'), ('10005', '10002', '郑州', '1'), ('10006', '10002', '信阳', '1'), ('10007', '10006', '息县', '1'), ('10008', '10003', '滨江', '1'), ('10009', '10003', '西湖', '1'), ('10010', '10003', '上城', '1'), ('10011', '10006', '罗山', '1'); COMMIT; -- ---------------------------- -- Procedure structure for `p_create_tree_node` -- ---------------------------- DROP PROCEDURE IF EXISTS `p_create_tree_node`; DELIMITER ;; CREATE DEFINER=`root`@`localhost` PROCEDURE `p_create_tree_node`(IN `in_pid` varchar(100)) BEGIN DECLARE v_has_child INT default 0; DECLARE v_rows INT default 0; DECLARE v_id VARCHAR(100) default ''; DECLARE v_pid VARCHAR(100) default ''; DECLARE v_nodename VARCHAR(100) default ''; DECLARE v_tree_id VARCHAR(100) default ''; DECLARE v_tree_pid VARCHAR(100) default ''; DECLARE v_done INT default 0; DECLARE v_cur CURSOR FOR SELECT id,pid,nodename from t_tlm_tree where `fast`=1 and pid=in_pid; DECLARE CONTINUE HANDLER FOR NOT FOUND SET v_done=1; SET @@max_sp_recursion_depth = 100; OPEN v_cur; loop_tag:LOOP FETCH v_cur INTO v_id,v_pid,v_nodename; IF v_done=1 THEN LEAVE loop_tag; END IF; IF STRCMP(in_pid,'-1')=0 THEN insert into t_tlm_device_tree(id,pid,nodename,oid) values('001',null,v_nodename,v_id); ELSE select id into v_tree_pid from t_tlm_device_tree where oid = in_pid; set v_rows = v_rows+1; set v_tree_id = concat('000',v_rows); set @len = LENGTH(v_tree_id)-2; set v_tree_id = SUBSTR(v_tree_id FROM @len); set v_tree_id = concat(v_tree_pid,v_tree_id); insert into t_tlm_device_tree(id,pid,nodename,oid) values(v_tree_id,v_tree_pid,v_nodename,v_id); END IF; set v_has_child = f_has_child_by_pid(v_id); IF v_has_child =1 THEN call p_create_tree_node(v_id); END IF; END LOOP loop_tag; CLOSE v_cur; END ;; DELIMITER ; -- ---------------------------- -- Procedure structure for `p_get_device_tree` -- ---------------------------- DROP PROCEDURE IF EXISTS `p_get_device_tree`; DELIMITER ;; CREATE DEFINER=`root`@`localhost` PROCEDURE `p_get_device_tree`() BEGIN DECLARE v_pid VARCHAR(100) default '-1'; DROP TEMPORARY TABLE IF EXISTS t_tlm_device_tree; CREATE TEMPORARY TABLE t_tlm_device_tree ( id varchar(100), pid varchar(100), nodename varchar(100), oid int(100), PRIMARY KEY (id) ); call p_create_tree_node(v_pid); select * from t_tlm_device_tree; TRUNCATE TABLE t_tlm_device_tree; DROP TEMPORARY TABLE IF EXISTS t_tlm_device_tree; END ;; DELIMITER ; -- ---------------------------- -- Function structure for `f_has_child_by_pid` -- ---------------------------- DROP FUNCTION IF EXISTS `f_has_child_by_pid`; DELIMITER ;; CREATE DEFINER=`root`@`localhost` FUNCTION `f_has_child_by_pid`(`f_pid` varchar(100)) RETURNS int(11) BEGIN DECLARE v_ret int default 0; select count(1) into @num from t_tlm_tree where pid=f_pid and `fast`=1; IF @num >0 THEN set v_ret = 1; END IF; return v_ret; END ;; DELIMITER ;
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InnoDBBufferPool reduces disk I/O by caching data and indexing pages, improving database performance. Its working principle includes: 1. Data reading: Read data from BufferPool; 2. Data writing: After modifying the data, write to BufferPool and refresh it to disk regularly; 3. Cache management: Use the LRU algorithm to manage cache pages; 4. Reading mechanism: Load adjacent data pages in advance. By sizing the BufferPool and using multiple instances, database performance can be optimized.

Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.

MySQL is worth learning because it is a powerful open source database management system suitable for data storage, management and analysis. 1) MySQL is a relational database that uses SQL to operate data and is suitable for structured data management. 2) The SQL language is the key to interacting with MySQL and supports CRUD operations. 3) The working principle of MySQL includes client/server architecture, storage engine and query optimizer. 4) Basic usage includes creating databases and tables, and advanced usage involves joining tables using JOIN. 5) Common errors include syntax errors and permission issues, and debugging skills include checking syntax and using EXPLAIN commands. 6) Performance optimization involves the use of indexes, optimization of SQL statements and regular maintenance of databases.

MySQL is suitable for beginners to learn database skills. 1. Install MySQL server and client tools. 2. Understand basic SQL queries, such as SELECT. 3. Master data operations: create tables, insert, update, and delete data. 4. Learn advanced skills: subquery and window functions. 5. Debugging and optimization: Check syntax, use indexes, avoid SELECT*, and use LIMIT.

MySQL efficiently manages structured data through table structure and SQL query, and implements inter-table relationships through foreign keys. 1. Define the data format and type when creating a table. 2. Use foreign keys to establish relationships between tables. 3. Improve performance through indexing and query optimization. 4. Regularly backup and monitor databases to ensure data security and performance optimization.

MySQL is an open source relational database management system that is widely used in Web development. Its key features include: 1. Supports multiple storage engines, such as InnoDB and MyISAM, suitable for different scenarios; 2. Provides master-slave replication functions to facilitate load balancing and data backup; 3. Improve query efficiency through query optimization and index use.

SQL is used to interact with MySQL database to realize data addition, deletion, modification, inspection and database design. 1) SQL performs data operations through SELECT, INSERT, UPDATE, DELETE statements; 2) Use CREATE, ALTER, DROP statements for database design and management; 3) Complex queries and data analysis are implemented through SQL to improve business decision-making efficiency.

The basic operations of MySQL include creating databases, tables, and using SQL to perform CRUD operations on data. 1. Create a database: CREATEDATABASEmy_first_db; 2. Create a table: CREATETABLEbooks(idINTAUTO_INCREMENTPRIMARYKEY, titleVARCHAR(100)NOTNULL, authorVARCHAR(100)NOTNULL, published_yearINT); 3. Insert data: INSERTINTObooks(title, author, published_year)VA


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