Có 20+ tài liệu thuộc chủ đề "MySQL cơ bản"
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Keith Murphy is a MySQL database administrator who has been using MySQL server since 1998. In addition to information about the company, Keith blogs at http://blog.paragon-cs.com , which he updates as frequently as possible with tricks, tips, and general information about MySQL server.. the MySQL community’s digital magazine about all things MySQL. It is his pleasure to work with some...
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SQLyog provides two tools to assist you — the auto-completion feature and SQL templates. The Query Browser is part of the GUI bundle that MySQL has available for free download from http://dev.mysql.com/downloads/gui-tools . Looking on the right-hand side of the screen you can see the databases on the connected server.. Some of the functionality that MySQL Administrator allows includes:. There...
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All of the changes in the ALTER TABLE are lost, even if the change did not cause the duplicate key error. See Chapter 6 for more details on all of the standard and nonstandard features of indexes in MySQL.. The LOW_PRIORITY option is specified just after the first word of the statement — for example, INSERT LOW_PRIORITY INTO tblname ....
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The four BLOB types are very similar to each other — the only differences are the maximum amount of data each can store and the overhead involved in storing the size of each record:. MySQL supports these data types with one exception — the DOUBLE PRECISION data type is simply named DOUBLE . However, you can change that behavior by...
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I n SQL theory, a key is a data constraint, such as a unique key or foreign key. A foreign key constraint ( FOREIGN KEY ) limits the data in a table by requiring that the set of values for the indexed data match data from outside the table.. UNIQUE KEY. PRIMARY KEY. FOREIGN KEY. A FOREIGN KEY requires a...
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MODIFIES SQL DATA — The stored routine may update data (with a DELETE , INSERT , or UPDATE command, for instance).. READS SQL DATA — The stored routine does not contain SQL to write data (as in MODI- FIES SQL DATA ) but does contain SQL that reads data (that is, SELECT statements). CONTAINS SQL — The stored routine does...
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The SELECT statement that defines the view must always be included in the ALTER VIEW statement, even if that part of the view definition is not being modified.. Similarly, the syntax of the ALTER VIEW statement is:. What happens if the server experiences a system failure between execution of the first and second statement? The $1000 is lost somewhere —...
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InnoDB storage engine options. A static variable that specifies the size of the cache for InnoDB data and indexes.. All of the InnoDB server variables are GLOBAL in nature.. Conversely, if the ratio is low, the size of the InnoDB buffer pool may need to be set higher.. Because of the log file flushing being different from the transaction commit,...
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Implementing Cache Tables Working with the Query Cache Utilizing Memcached. There is one other tradeoff of using the Event Scheduler — the query is run every 30 minutes, regardless of whether or not the information is used. Working with the Query Cache. Similar to the concept of a local cache of a web page, mysqld can compare a query to...
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The grant tables (user permissions) are stored in the mysql database. For this example assume a file sys- tem snapshot was performed at midnight of the 16th of September and the logs were flushed at the same time. Here is a listing of the binary log directory:. This was determined by looking at the timestamp of the log files, which...
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In addition, many of the configuration options can be controlled at server runtime.. Another function of the binary log is to enable replication. The contents of the binary log are any statements that occur in the server that could potentially modify the databases. The binary log index file is a plain text file that keeps track of the current binary...
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The open source program mysqltuner is a Perl script that is a part of the default package distribution for some operating systems. There are three checks in the General Statistics section. It prints out a list of the total data stored in each table type and ends with a count of fragmented tables.. The next line gives the percentage of...
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The query we are analyzing returns every value of the return_date field. Indexes can make data retrieval faster because they are ordered subsets of data, and can be searched faster than the entire set of data, which may be ordered differently than an index. ON the WEBSITE More information on how to create and use subqueries can be found on...
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definition extensions, 147–150 flushing, 63. implementing cache, 424–427 lock priority, 129. maintenance extensions, 150–156 Maria configuration, 398–400 MERGE, 510–513. MySQL deviations, 106 mysqlslap, 551–552 partitioning. query analysis. See query analysis scans vs. server maintenance extensions, 130–131 setting characters sets and collation, 101 SHOW commands, 146–147. SHOW CREATE commands, 138 SQL mode definitions, 206–207 SQL modes, 210–211. system, 476–478 types, 375....
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SCHEMA_NAME — The name of the database, such as sakila. DEFAULT_CHARACTER_SET_NAME — The default character set of the database. DEFAULT_COLLATION_NAME — The default collation of the database. TABLE_SCHEMA — The name of the database, such as sakila. TABLE_NAME — The name of the table.. ENGINE — The storage engine of the table, such as InnoDB. VERSION — The version of...
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info , which stands for ‘‘the field information of the hello system view in the mysql information schema.’’. MySQL Proxy. MySQL Proxy or Linux-HA Heartbeat (described later in this chapter) can be used with replication to achieve an automated failover solution.. MySQL Proxy or Linux-HA Heartbeat can be used with a SAN for automated failover.. MySQL Proxy is a technology...
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and SQL keywords ( TK_SQL_SELECT , TK_SQL_FROM , TK_SQL_WHERE , TK_SQL_LIKE. There are no examples given, because each token name is the keyword with TK_SQL_ appended. For example, the token TK_SQL_ALTER corresponds to the SQL keyword ALTER. SQL Statement Keywords TK_SQL_ACCESSIBLE TK_SQL_ACTION TK_SQL_ADD TK_SQL_ALL TK_SQL_ALTER TK_SQL_ANALYZE TK_SQL_AND TK_SQL_AS TK_SQL_ASC. TK_SQL_ASENSITIVE TK_SQL_BEFORE TK_SQL_BETWEEN TK_SQL_BIGINT. TABLE A-8 (continued ) SQL Statement Keywords...
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Wiki ( http://forge.mysql.com/wiki/Main Page. The official documentation for MySQL is online at http://dev.mysql.com/doc . The reference manuals for MySQL 5.0 and 5.1 have been translated into several different for- mats and languages. Visit http://dev.mysql.com/doc/#refman to see a matrix of the documentation available.. At the time of this writing, the official reference manual for MySQL 6.0 is only available in English,...
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This book, of course, is the story of MySQL.. The History of MySQL. This story actually goes back to 1979 when MySQL’s inventor, Michael Widenius (a.k.a. By May 1995, TcX had a database that met its internal needs—MySQL 1.0. The result is a very flexible copyright that makes MySQL “more free” than mSQL. Eventually, Monty released MySQL under the GPL...
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The rest of the book covers the use of MySQL to design, build and support the type of applications important to users like you.. A database is, simply put, a collection of data. This database works (or maybe it doesn’t) because the size of the database is incredibly small. So, restating our definition, we will define a database as an...