mysql pivot table

rules and then goes to manipulate it. What is a partition? partitions and sub-tables are similar, and are broken down by rules. The difference is that the table divides the large table into several separate entity tables, while partitioning divides the data into multiple locations, which can be the same disk or on different machines. After partitioning, the surface is still a

KEY (su_teacher) REFERENCES teacher (te_id) --ALTER Table Main Table name ADD CONSTRAINT foreign key name FOREIGN key (primary table as column name for foreign key) REFERENCES from table name (from table column name) Student Account Association

difference is that the table divides the large table into several separate entity tables, while partitioning divides the data into multiple locations, which can be the same disk or on different machines. After partitioning, the surface is still a table, but the data is hashed to multiple locations. When the app reads or writes a large

Mysql command to view the table structure showcolumnsfrom table name; 1. Copy the table structure and data to the new table CREATETABLE new table SELECT * FROM old table this method wil

A summary of the MySQL cross-table update was written a few days ago, and today we look at the cross-table deletions.After Mysql4.0, MySQL began to support cross-table Delete.MySQL can delete multiple table records in one SQL stat

Label: in the MySQL Sub-Library table we are generally based on a large amount of time on the MySQL database an optimization approach, below I briefly introduce MySQL sub-table and the simple way of the library. 1, the sub-database is obvious, a main

Test environment centos7.3+mysql5.7A table using the InnoDB engine, the table name Innodb_testThe other table uses the MyISAM engine, and the table name Innodb_testIn the event of a transactional operation, see what happens.Table structure same as only 3 fields Id,name, Money+-------+---------------+------+-----+------

MySQL storage engine (Table type) selection, mysql Engine Unlike most databases, MySQL has a storage engine concept. You can select different storage engines based on data storage requirements. This blog introduces the storage engine in MySQL.

MySQL copy table or table data is commonly used to summarize the statements.If we have one of the following tables:ID Username password-----------------------------------1 Admin ************* 2 Sameer ************* 3 Stewart #SQLCREATETABLEIFNotEXISTS' Admin ' (' ID 'int (6) unsigned NOT null auto_increment, ' username ' varchar (50) not null default ", ' pass

Label:MySQL query data table data record (including multi-table query) MySQL query data table data record (including multi-table query)Transferred from: http://www.baike369.com/content/?id=5355 The purpose of creating a database in

The application of Windows under the deployment of Linux, using the features of the Quartz cluster, so built the MYSQL intermediate table, a start to see the error:invocation of Init method failed; nested Exception is Org.quartz.JobPersistenceException:Couldn ' t retrieve trigger:table ' unmijob. Qrtz_triggers ' doesn ' t exist [see nested Exception:com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException:

Copy the table in MySQL and copy the Old_table table to the New_table table. 1. Do not copy table data, only copy structure. The code is as follows Copy Code CREATE TABLE new_table like Old_table2

How to create an associated mysql table-PHP, which is usually used for single-table operations, has never made any progress. recently, after reading a few open-source articles, it has become more dynamic. Books and videos that have been read all the time are operations on a single table. Now we need to implement a fu

different, cold data using MyIsam can have better query data. Active data, can use Innodb, can have better update speed.Second, the cold data is more from the library configuration, because more operations are queries, so as to speed up the query. For thermal data, it is possible to handle the horizontal table of the main library relatively.In fact, for some special active data, you can also consider the use of Memcache, Redis and other caches, such

Copy an entire table The code is as follows Copy Code CREATE TABLE new_table select * from Old_table; Copy tables, do not copy data The code is as follows Copy Code CREATE TABLE new_table SELECT * from old_table where 0; Other additional features, such as primary keys, indexes, and so o

--MySQL 5.7 CLUSTER NDB 7.5--Create the undo logfile GroupCreate logfile Group lg_1ADD undofile ' Undo_1.log 'Initial_size 1024MUndo_buffer_size 8MENGINE Ndbcluster;--Increase logfileALTER LogFile Group lg_1ADD undofile ' Undo_2.log 'Initial_size 1024MENGINE Ndbcluster;--Create TablespaceCREATE tablespace Ts1ADD datafile ' Data_1.dat 'Use LOGFILE GROUP lg_1Initial_size 1024MENGINE Ndbcluster;--Expansion TablespaceALTER tablespace Ts_1ADD datafile ' Da

MYSQL Tutorial: MySQL server permission table the MySQL server uses the permission table to control user access to the database. The permission table is stored in the mysql database and

Tags: image union receive generates CTime database ref common contentOne: Overview When we design a system, we need to consider the system after a period of time, the table data volume about how much, if in the early days, it can be estimated that a certain number of table data is very large (such as chat message table), it is necessary to create a

Benefits of MySQL using partitioned tables: 1, you can put some of the data in the collation of a partition, you can reduce the number of server check data to speed up the query.2, easy maintenance, delete the old data by deleting the partition.3, partition data can be distributed to different physical locations, can do distributed effective use of multiple hard drives. MySQL can establish partitions of f

Label: Using the innodb_export_import.py script: Https://github.com/thecpaneladmin/innodb-tools To install the Mysql-python module : Shell > Yum Install mysql-python-y Step One: Modify the my.cnf file Add innodb_force_recovery = 4 parameter, restart MySQL, block all read and write operations, Step Two: Execute the script to export the data from the InnoDB