A few days ago, the company came to a new person and accidentally kicked off the power supply. At that time, my machine was still running the server program.
The above is the background. When I restart the service, I find that connection to the
MySQL cluster is a highly practical and redundant MySQL version suitable for distributed computing environments. It uses the NDB Cluster Storage engine and allows multiple MySQL servers to run in one cluster.
MySQL cluster is a technology that
MySQL will optimize SQL statements, and indexes will still be used if there are no more than a certain number of conditions after in.MySQL determines whether to use an index based on the index length and the number of conditions following in.
In
1. Create a database:Create database database_name;Two methods for creating a database in php: mysql_create_db (), mysql_query ())$ Conn = mysql_connect ("localhost", "username", "password") orDie ("cocould not connect to localhost ");1.Mysql_create_
Error:1)Caused by changing the master:Last_IO_Error: error connecting to master 'repl1 @ IP: 100'-retry-time: 60 retries
2)Stop the slave process without unlocking:Mysql> stop slave;ERROR 1192 (HY000): Can't execute the given command because you
MySQL Semisynchronous Replication
In addition to the built-in asynchronous replication mechanism, MySQL5.5 also provides interfaces to support semi-synchronous replication.
Disadvantages of asynchronous replication:
MySQL replication is asynchronous
There is no theoretical basis as described below, which is purely an experience.
MySQL uses version 4.1 or later, and uses the default for whatever character set it is. You do not need to set MySQL.
Then an example of using GB2312 and UTF-8 is
A basic example
Linux MySQL changes the directory location of the MySQL database
The default data file storage directory of MySQL is/var/lib/mysql. To move the directory to/home/data, perform the following steps:
1. Create a data directory under the
The "build" mentioned in this article is not just about creating a database or a table, but about whether your database and table can cope with various events during project operations, next, let me talk about some of the problems I encountered in
When I reinstall MySQL, I encountered some problems. I found a solution on the Internet and summarized it as follows:
1. Before re-installing MySQL, you must uninstall and completely delete MySQL.
1. Uninstall the Control Panel first.
2.
I watched a video of PhP100 in the afternoon.
It is also a bit rewarding.
A self-written SQL function of findall in it:
Public Function findall ($ table) { $ this-> query ("select * from $ table"); }
It turned out to be so simple that I was
Ask a question MySQL Recordset does not support the MoveNext method?
function GetTags ($device)
{
$sql = "Select TagName from TagList where device= ' $device '";
$rs = mysql_query ($sql);
while (! $rs->eof)//Save the Recordset to a two-dimensional
Ask a few questions about the MySQL return array
Is 1.mysql_fetch_array performance worse than Row,assoc?
2.mysql_fetch_row output method only $row[num] This output method, it is not very troublesome in the case of no data table comparison?
3. Now I
Today, the OPS group's classmates came to me, said the backup pool file description is not displayed, and it is not displayed from the beginning of 20th, the previous file description can be displayed, and 20th of their uploaded backup data is
MySQL query with quotes and no quotes difference
When the database field ID is an integral type
Select ID from table where id=1
And
Select ID from table where id= ' 1 '
Two SQL is OK, but the first SQL does not have to be implicitly converted,
The InnoDB engine is different in statistics and MyISAM, and MyISAM has a built-in counter, so when you use the Select COUNT (*) from table, you can directly retrieve data from the counter. And InnoDB must be scanned all the time to get the total
The following summarizes the MySQL conversion Oracle several points of attention, I hope to help.
1. Automatic growth of data type processing
MySQL has an automatically growing data type, and the data value is automatically obtained when you
In E-commerce, there will often be a small number of inventory, the purchase of the person is particularly large, concurrency in the case of how to ensure that the number of goods will not be purchased multiple times.
In fact very simple, use the
Compare the similarities and differences, and deepen the memory.
This article "Compared with the MSSQL learning MySQL (Seven)" is the same, the same place slightly brought, different places I will give examples, thank you for your support O (∩_∩) o
Innodb_flush_log_at_trx_commit determines when the transaction log Write,flush
Innodb_flush_method determines how the log and data files are write and flush. "Show variables" shows that the variable is empty, which means that the default value is
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