Mysql Varchar Length

The initial key value comparison, MongoDB victory faster, and this has always been our goal to give the database system MySQL dragster the speed of the disk as its biggest obstacle, this really can make sense? Let's just make an obstacle, what about the solution? If an obstacle limits your dragster, you can choose to bypass it faster or improve on the computer. For example: Avoid the use of disk, as much as possible memory in lieu of faster disk (such as SSD) in fact, this is not good analogy, because the limit from the disk is like ...

As long as you master the following method, you can basically get the mysql database. First, the connection MYSQL format: mysql-h host address-u username-p user password 1, Example 1: Connect to the local MySQL: First open the DOS window and then enter the directory mysqlbin, then type the command mysql -uroot - p, after the carriage return prompts you to lose the password, if you just installed MYSQL, super user root is no password, so enter directly into MYSQL, MYS ...

This article mainly introduces the practical steps of character (string) in MySQL database. We all know that the character (string) of MySQL database is often used in practice, so you know more about it is still good Hopefully this will bring you some help in this regard. MySQL database character (string) class Do not think that the character type is CHAR CHAR and VARCHAR difference is that CHAR is a fixed length, as long as you define a field is CHAR (10), no matter whether your stored data reached 10 bytes , ...

1, MySQL exists text and blob: (1), the same in the text or BLOB column storage or retrieval process, there is no case conversion, when not running in strict mode, if you assign a BLOB or text column exceeds the maximum length of the column type value, the value is intercepted to ensure that the appropriate. If the truncated character is not a space, a warning is generated. Using strict SQL mode produces an error, and the value is rejected rather than intercepted and given a warning. Blob and text columns cannot have default values. When a blob is saved or retrieved ...

Intermediary transaction SEO diagnose Taobao guest Cloud host technology Lobby database optimization is a very complex task, because it ultimately requires a good understanding of system optimization. 　　Even though the system or application system does not know much about the optimization effect is good, but if you want to optimize the effect of better, then you need to know more about it. 1, the optimization of the system to run faster the most important factor is the basic design of the database. 　　And you have to be aware of what your system is going to do, and the bottlenecks that exist. The most common system bottlenecks are as follows: ...

The database holds one or more tables. Create a Database The CREATE DATABASE statement is used to create a database in MySQL. Syntax CREATE DATABASE database_name In order for PHP to execute the above statement, we must use the mysql_query () function. This function is used to send queries or commands to the MySQL connection. Example In the following example, we create a database named "my_db": ...

First, the importance of the index The index is used to quickly find a column in a particular value of the line. Instead of using an index, MySQL must start with the first record and then read the entire table until it finds the relevant row. The larger the table, the more time it takes. If the table in the query column index, MySQL can quickly reach a location to search the middle of the data file, there is no need to see all the data. Note that if you need to access most of the rows, sequential reads are much faster since we avoid disk searches. If you use Xinhua Dictionary to find "Zhang" the Chinese characters, do not use the directory, then ...

mysql tutorial to modify the table / field to add / delete table index create table test (blob_col blob, index (blob_col (10))); In mysql 5.1, myisam and innodb table prefix can reach 1000 bytes long. Note that the prefix limit should be measured in bytes, while the prefix length in the create table statement is interpreted as the number of characters. Must be considered when specifying the prefix length for columns that use multi-byte character sets. ...

Today found that the deder MYSQL time field, are used `senddata` int (10) unsigned NOT NULL DEFAULT '0'; Then find this article online, it seems that if the time field is involved in the operation, int better, a To retrieve the field without conversion operations, directly for time comparison! Second, the efficiency is higher as described below. In the final analysis: int instead of the data type, more efficient. Environment: Windows XP PHP Versio ...

This is a use mysql php instance user registration code, is relatively simple, is to submit the html data submitted to the mysql database tutorial. * / include ('global.php'); if ($ _ post ['sub']) {$ user = $ _post ['username']; $ pwd = md5 ($ _ post ['p ...