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| From: | jon | Date: | October 21 2006 3:22pm |
| Subject: | svn commit - mysqldoc@docsrva: r3693 - trunk/refman-5.0 | ||
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Author: jstephens Date: 2006-10-21 15:22:15 +0200 (Sat, 21 Oct 2006) New Revision: 3693 Log: Renaming old-faq.xml to faqs.xml Turning it into a chapter rather than a section Added: trunk/refman-5.0/faqs.xml Removed: trunk/refman-5.0/old-faq.xml Added: trunk/refman-5.0/faqs.xml =================================================================== --- trunk/refman-5.0/faqs.xml (rev 0) +++ trunk/refman-5.0/faqs.xml 2006-10-21 13:22:15 UTC (rev 3693) Changed blocks: 1, Lines Added: 1882, Lines Deleted: 0; 44940 bytes @@ -0,0 +1,1882 @@ +<?xml version="1.0" encoding="utf-8"?> +<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" +"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" +[ + <!ENTITY % fixedchars.entities SYSTEM "../refman-common/fixedchars.ent"> + %fixedchars.entities; + <!ENTITY % urls.entities SYSTEM "../refman-common/urls.ent"> + %urls.entities; + <!ENTITY % versions.entities SYSTEM "versions.ent"> + %versions.entities; +]> +<chapter id="faqs"> + + <title>MySQL ¤t-series; Technical FAQ</title> + + <section id="faqs-general"> + + <title>MySQL ¤t-series; FAQ — General</title> + + <qandaset defaultlabel="qanda"> + + <qandaentry id="faqs-general-production"> + + <question> + + <para> + When did MySQL ¤t-series; become production-ready + (GA)? + </para> + + </question> + + <answer> + + <para> + MySQL 5.0.15 was released for production use on 19 October + 2005. We are now working on MySQL 5.1, which is currently in + beta. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-subqueries"> + + <question> + + <para> + Can MySQL ¤t-series; do subqueries? + </para> + + </question> + + <answer> + + <para> + Yes. MySQL supports subqueries since version 4.1 See + <xref linkend="subqueries"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-multi-table"> + + <question> + + <para> + Can MySQL ¤t-series; do multi-table inserts and + updates? + </para> + + </question> + + <answer> + + <para> + Yes. Multi-table <literal>UPDATE</literal> and + <literal>DELETE</literal> were actually implemented in MySQL + 4.0, with enhancements added in MySQL 4.1. See + <xref + linkend="update"/>, and + <xref linkend="delete"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-query-cache"> + + <question> + + <para> + Does MySQL ¤t-series; have a Query Cache? Does it work + on Server, Instance or Database? + </para> + + </question> + + <answer> + + <para> + Yes. The Query Cache was introduced in MySQL 4.0, and + operates on the server level. It caches complete result + sets, matched with the original query string. If an exactly + identical query is made (which often happens, particularly + in web applications), no parsing or execution is necessary, + the result is sent directly from the cache. Various tuning + options are available. See <xref linkend="query-cache"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-sequences"> + + <question> + + <para> + Does MySQL ¤t-series; have Sequences? + </para> + + </question> + + <answer> + + <para> + No. However, MySQL has an <literal>AUTO_INCREMENT</literal> + system, which in MySQL ¤t-series; can also handle + inserts in a multi-master replication setup. With the + <option>--auto-increment-increment</option> and + <option>--auto-increment-offset</option> startup options, + you can set each server to generate auto-increment values + that don't conflict with other servers. The + <option>--auto-increment-increment</option> value should be + greater than the number of servers, and each server should + have a unique offset. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-now-fractional-seconds"> + + <question> + + <para> + Does MySQL 5.0 have a <literal>NOW()</literal> function with + fractions of seconds? + </para> + + </question> + + <answer> + + <para> + No. This is on the MySQL roadmap as a <quote>rolling + feature</quote>. This means that it is not a flagship + feature, but will be implemented, development time + permitting. Specific customer demand may change this + scheduling. + </para> + + <para> + However, MySQL does parse time strings with a fractional + component. See <xref linkend="time"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-multi-cores"> + + <question> + + <para> + Does MySQL ¤t-series; work with mutli-core + processorsd? + </para> + + </question> + + <answer> + + <para> + Yes. MySQL is fully multi-threaded, and will make use of + multiple CPUs, provided that the operating system supports + them. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-myisam-hot-backup"> + + <question> + + <para> + Is there a hot backup tool for MyISAM like InnoDB Hot + Backup? + </para> + + </question> + + <answer> + + <para> + This is currently under development for a future MySQL + release. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-fk-error-reporting"> + + <question> + + <para> + Is there any improvement in error reporting when Foreign Key + fails (i.e. currently does not report which column and + reference failed)? + </para> + + </question> + + <answer> + + <para> + The foreign key support in InnoDB has seen improvements in + each major version of MySQL. However, global foreign key + support (i.e., generically for all storage engines) is + scheduled for MySQL 5.2 and should resolve any inadequacies + in the current storage engine specific implementation. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-general-acid"> + + <question> + + <para> + Can MySQL ¤t-series; perform ACID transactions? + </para> + + </question> + + <answer> + + <para> + Yes. MySQL has supported transactions for years now, since + 3.23-Max and all versions 4.0 and above. The InnoDB storage + engine offers full ACID transactions with row-level locking, + multi-versioning, non-locking repeatable reads, and all four + SQL standard isolation levels. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-storage-engines"> + + <title>MySQL ¤t-series; FAQ — Storage Engines</title> + + <qandaset defaultlabel="qanda"> + + <qandaentry id="faqs-storage-engines-new-engines"> + + <question> + + <para> + What are the new Storage Engines in MySQL ¤t-series;? + </para> + + </question> + + <answer> + + <para> + The <literal>FEDERATED</literal> storage engine, new in My + SQL ¤t-series;, allows the server to access tables in + other (remote) servers. See + <xref + linkend="federated-storage-engine"/>. + </para> + + <para> + MySQL 4.1 already added other new storage engines, such as + ARCHIVE, CSV and NDB (Cluster). + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-storage-engines-archive"> + + <question> + + <para> + What are the unique benefits of the + <literal>ARCHIVE</literal> storage engine? + </para> + + </question> + + <answer> + + <para> + The <literal>ARCHIVE</literal> Storage Engine, added in + MySQL 4.1, is ideally suited for storing large amounts of + data (without indexes) in a very small footprint, and + selects using table scans. See + <xref + linkend="archive-storage-engine"/>, for + details. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-storage-engines-new-features"> + + <question> + + <para> + Do the new features in MySQL ¤t-series; apply to all + storage engines? + </para> + + </question> + + <answer> + + <para> + The general new features such as views, stored procedures, + triggers, <literal>INFORMATION_SCHEMA</literal>, precision + math (<literal>DECIMAL</literal> column type), and the + <literal>BIT</literal> column type, apply to all storage + engines. There are also additions and changes for specific + storage engines. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-sql-modes"> + + <title>MySQL ¤t-series; FAQ — Server SQL Mode</title> + + <qandaset defaultlabel="qanda"> + + <qandaentry id="faqs-sql-modes-what"> + + <question> + + <para> + What are server SQL modes? + </para> + + </question> + + <answer> + + <para> + Server SQL modes define what SQL syntax MySQL should support + and what kind of data validation checks it should perform. + This makes it easier to use MySQL in different environments + and to use MySQL together with other database servers. The + MySQL Server apply these modes individually to different + clients. For more information, see + <xref + linkend="server-sql-mode"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faq-sql-modes-how-many"> + + <question> + + <para> + How many server SQL modes are there? + </para> + + </question> + + <answer> + + <para> + Quite a few, as each mode can be individually switched on + and off. See <xref linkend="server-sql-mode"/>, for a + complete list of available modes. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-sql-modes-determining"> + + <question> + + <para> + How do you determine the server SQL mode? + </para> + + </question> + + <answer> + + <para> + You can set the default SQL mode (for + <command>mysqld</command> startup) with the + <option>--sql-mode</option> option. Using the statement + <literal>SET [SESSION|GLOBAL] + sql_mode='<replaceable>modes</replaceable>'</literal>, you + can change the settings from within a connection, either + locally to the connection, or to take effect globally. You + can retrieve the current mode by issuing a <literal>SELECT + @@sql_mode</literal> statement. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-sql-modes-scope"> + + <question> + + <para> + Is the mode dependent on the database or connection? + </para> + + </question> + + <answer> + + <para> + A mode is not linked to a particular database. Modes can be + set locally to the session (connection), or globally for the + server. you can change these settings using <literal>SET + [SESSION|GLOBAL] + sql_mode='<replaceable>modes</replaceable>'</literal>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-sql-modes-extending"> + + <question> + + <para> + Can the rules for strict mode be extended? + </para> + + </question> + + <answer> + + <para> + When we refer to <emphasis>strict mode</emphasis>, we mean a + mode where at least one of the modes + <literal>TRADITIONAL</literal>, + <literal>STRICT_TRANS_TABLES</literal>, or + <literal>STRICT_ALL_TABLES</literal> is enabled. Options can + be combined, so you can add additional restrictions to a + mode. See <xref linkend="server-sql-mode"/>, for more + information. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-sql-modes-performance"> + + <question> + + <para> + Does strict mode impact performance? + </para> + + </question> + + <answer> + + <para> + Of course, a setting that requires intensive validation of + input data requires some additional time. While the + performance impact is not that great, if you do not require + such validation (perhaps your application already handles + all of this), then MySQL gives you the option of leaving + strict mode disabled. However — if you do require it + — strict mode can provide such validation. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-sql-modes-default"> + + <question> + + <para> + What is the default server SQL mode when My SQL + ¤t-series; is installed? + </para> + + </question> + + <answer> + + <para> + By default, no special modes are enabled. See + <xref + linkend="server-sql-mode"/>, for + information about all available modes and the default + behaviour. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-stored-procs"> + + <title>MySQL ¤t-series; FAQ — Stored Procedures</title> + + <qandaset defaultlabel="qanda"> + + <qandaentry id="faqs-stored-procs-support"> + + <question> + + <para> + Does MySQL ¤t-series; support stored procedures? + </para> + + </question> + + <answer> + + <para> + Yes. MySQL ¤t-series; supports two types of stored + routines — stored procedures and stored functions. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-docs"> + + <question> + + <para> + Where can I find documentation for MySQL stored procedures + and stored functions? + </para> + + </question> + + <answer> + + <para> + See <xref linkend="stored-procedures"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-forum"> + + <question> + + <para> + Is there a discussion forum for MySQL stored procedures? + </para> + + </question> + + <answer> + + <para> + Yes. See + <ulink + url="http://forums.mysql.com/list.php?98" + >http://forums.mysql.com/list.php?98</ulink>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-spec"> + + <question> + + <para> + Where can I find the ANSI SQL 2003 specification for stored + procedures? + </para> + + </question> + + <answer> + + <para> + Unfortunately, the official specifications are not freely + available (ANSI makes them available for purchase). However, + there are books — such as <citetitle>SQL-99 Complete, + Really</citetitle> by Peter Gulutzan and Trudy Pelzer + — which give a comprehensive overview of the standard, + including coverage of stored procedures. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-management"> + + <question> + + <para> + How do you manage stored routines? + </para> + + </question> + + <answer> + + <para> + It is always good practice to use a clear naming scheme for + your stored routines. You can manage stored procedures with + <literal>CREATE [FUNCTION|PROCEDURE]</literal>, + <literal>ALTER [FUNCTION|PROCEDURE]</literal>, <literal>DROP + [FUNCTION|PROCEDURE]</literal>, and <literal>SHOW CREATE + [FUNCTION|PROCEDURE]</literal>. You can obtain information + about existing stored procedures using the + <literal>ROUTINES</literal> table in the + <literal>INFORMATION_SCHEMA</literal> database (see + <xref + linkend="routines-table"/>). + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-view-all"> + + <question> + + <para> + Is there a way to view all stored procedures and stored + functions in a given database? + </para> + + </question> + + <answer> + + <para> + Yes. For a database named <replaceable>dbname</replaceable>, + use this query on the + <literal>INFORMATION_SCHEMA.ROUTINES</literal> table: + </para> + +<programlisting> +SELECT ROUTINE_TYPE, ROUTINE_NAME + FROM INFORMATION_SCHEMA.ROUTINES + WHERE ROUTINE_SCHEMA='<replaceable>dbname</replaceable>'; +</programlisting> + + <para> + For more information, see + <xref + linkend="routines-table"/>. + </para> + + <para> + The body of a stored routine can be viewed using + <literal>SHOW CREATE FUNCTION</literal> (for a stored + function) or <literal>SHOW CREATE PROCEDURE</literal> (for a + stored procedure). See + <xref linkend="show-create-procedure" + />, for + more information. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-storage"> + + <question> + + <para> + Where are stored procedures stored? + </para> + + </question> + + <answer> + + <para> + In the <literal>proc</literal> table of the + <literal>mysql</literal> system database. However, you + should not access the tables in the system database + directly. Instead, use <literal>SHOW CREATE + FUNCTION</literal> to obtain information about stored + functions, and <literal>SHOW CREATE PROCEDURE</literal> to + obtain information about stored procedures. See + <xref + linkend="show-create-procedure"/>, for + more information about these statements. + </para> + + <para> + You can also query the <literal>ROUTINES</literal> table in + the <literal>INFORMATION_SCHEMA</literal> database — + see <xref linkend="routines-table"/>, for information about + this table. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-packages"> + + <question> + + <para> + Is it possible to group stored procedures or stored + functions into packages? + </para> + + </question> + + <answer> + + <para> + No. This is not supported in MySQL ¤t-series;. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-call-other-sps"> + + <question> + + <para> + Can a stored procedure call another stored procedure? + </para> + + </question> + + <answer> + + <para> + Yes. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-call-triggers"> + + <question> + + <para> + Can a stored procedure call a trigger? + </para> + + </question> + + <answer> + + <para> + A stored procedure can execute an SQL statement, such as an + <literal>UPDATE</literal>, that causes a trigger to fire. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-access-tables"> + + <question> + + <para> + Can a stored procedure access tables? + </para> + + </question> + + <answer> + + <para> + Yes. A stored procedure can access one or more tables as + required. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-raising-errors"> + + <question> + + <para> + Do stored procedures have a statement for raising + application errors? + </para> + + </question> + + <answer> + + <para> + Not in MySQL ¤t-series;. The SQL standard + <literal>SIGNAL</literal> and <literal>RESIGNAL</literal> + statements are on the TODO. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-exception-handling"> + + <question> + + <para> + Do stored procedures provide exception handling? + </para> + + </question> + + <answer> + + <para> + MySQL implements <literal>HANDLER</literal> definitions + according to the SQL standard. See + <xref + linkend="declare-handlers"/>, for + details. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-return-result-sets"> + + <question> + + <para> + Can MySQL ¤t-series; stored routines return result + sets? + </para> + + </question> + + <answer> + + <para> + Yes. If you perform an ordinary <literal>SELECT</literal> + inside a stored procedure or stored function, the result set + is returned directly to the client. You need to use the + MySQL 4.1 client-server protocol for this to work. This + means that — for instance — in PHP, you need to + use the <literal>mysqli</literal> extension rather than the + old <literal>mysql</literal> extension. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-with-recompile"> + + <question> + + <para> + Is + +<literallayout>WITH RECOMPILE</literallayout> + + supported for stored procedures? + </para> + + </question> + + <answer> + + <para> + Not in MySQL ¤t-series;. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-mod-plsql"> + + <question> + + <para> + Is there a MySQL equivalent to using + <literal>mod_plsql</literal> as a gateway on Apache to talk + directly to a stored procedure in the database? + </para> + + </question> + + <answer> + + <para> + There is no equivalent in MySQL ¤t-series;. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-arrays"> + + <question> + + <para> + Can I pass an array as input to a stored procedure? + </para> + + </question> + + <answer> + + <para> + Not in MySQL ¤t-series;. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-cursors-in"> + + <question> + + <para> + Can I pass a cursor as an <literal>IN</literal> parameter to + a stored procedure? + </para> + + </question> + + <answer> + + <para> + In MySQL ¤t-series;, cursors are available inside + stored procedures only. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-cursors-out"> + + <question> + + <para> + Can I return a cursor as an <literal>OUT</literal> parameter + from a stored procedure? + </para> + + </question> + + <answer> + + <para> + In MySQL ¤t-series;, cursors are available inside + stored procedures only. However, if you do not open a cursor + on a <literal>SELECT</literal>, the result will be sent + directly to the client. You can also <literal>SELECT + INTO</literal> variables. See <xref linkend="select"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-return-value"> + + <question> + + <para> + Can I print out a variable's value within a stored procedure + for debugging purposes? + </para> + + </question> + + <answer> + + <para> + Yes. If you perform an ordinary <literal>SELECT</literal> + inside a stored procedure or stored function, the result set + is returned directly to the client. You will need to use the + MySQL 4.1 client-server protocol for this to work. This + means that — for instance — in PHP, you need to + use the <literal>mysqli</literal> extension rather than the + old <literal>mysql</literal> extension. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-stored-procs-transaction-support"> + + <question> + + <para> + Can I commit or roll back transactions inside a stored + procedure? + </para> + + </question> + + <answer> + + <para> + Yes. However, you cannot perform transactional operations + within a stored function. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-triggers"> + + <title>MySQL ¤t-series; FAQ - Triggers</title> + + <qandaset defaultlabel="qanda"> + + <qandaentry id="faqs-triggers-docs"> + + <question> + + <para> + Where can I find the documentation for MySQL + ¤t-series; triggers? + </para> + + </question> + + <answer> + + <para> + See <xref linkend="triggers"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry> + + <question> + + <para> + Is there a discussion forum for MySQL Triggers? + </para> + + </question> + + <answer> + + <para> + Yes. It is available at + <ulink + url="http://forums.mysql.com/list.php?99" + >http://forums.mysql.com/list.php?99</ulink>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-statement-or-row-level"> + + <question> + + <para> + Does MySQL ¤t-series; have statement-level or + row-level triggers? + </para> + + </question> + + <answer> + + <para> + In MySQL ¤t-series;, all triggers are <literal>FOR + EACH ROW</literal> — that is, the trigger is activated + for each row that is inserted, updated, or deleted. MySQL + ¤t-series; does not support triggers using + <literal>FOR EACH STATEMENT</literal>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-default"> + + <question> + + <para> + Are there any default triggers? + </para> + + </question> + + <answer> + + <para> + Not explicitly. MySQL does have specific special behavior + for some <literal>TIMESTAMP</literal> columns, as well as + for columns which are defined using + <literal>AUTO_INCREMENT</literal>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-management"> + + <question> + + <para> + How are triggers managed in MySQL? + </para> + + </question> + + <answer> + + <para> + In MySQL ¤t-series;, triggers can be created using the + <literal>CREATE TRIGGER</literal> statement, and dropped + using <literal>DROP TRIGGER</literal>. See + <xref + linkend="create-trigger"/>, and + <xref + linkend="drop-trigger"/>, for more about + these statements. + </para> + + <para> + Information about triggers can be obtained by querying the + <literal>INFORMATION_SCHEMA.TRIGGERS</literal> table. See + <xref linkend="triggers-table"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-view-all"> + + <question> + + <para> + Is there a way to view all triggers in a given database? + </para> + + </question> + + <answer> + + <para> + Yes. You can obtain a listing of all triggers defined on + database <literal>dbname</literal> using a query on the + INFORMATION_SCHEMA.TRIGGERS table such as the one shown + here: + </para> + +<programlisting> +SELECT TRIGGER_NAME, EVENT_MANIPULATION, EVENT_OBJECT_TABLE, ACTION_STATEMENT + FROM INFORMATION_SCHEMA.TRIGGERS + WHERE TRIGGER_SCHEMA='<replaceable>dbname</replaceable>'; +</programlisting> + + <para> + For more information about this table, see + <xref + linkend="triggers-table"/>. + </para> + + <para> + You can also use the <literal>SHOW TRIGGERS</literal> + statement, which is specific to MySQL. See + <xref + linkend="show-triggers"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-storage"> + + <question> + + <para> + Where are triggers stored? + </para> + + </question> + + <answer> + + <para> + Triggers are currently stored in <filename>.TRG</filename> + files, with one such file one per table. In other words, a + trigger belongs to a table. + </para> + + <para> + In the future, we plan to change this so that trigger + information will be included in the + <filename>.FRM</filename> file that defines the structure of + the table. We also plan to make triggers database-level + objects — rather than table-level objects as they are + now — to bring them into compliance with the SQL + standard. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-stored-procs"> + + <question> + + <para> + Can a trigger call a stored procedure? + </para> + + </question> + + <answer> + + <para> + Yes. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-table-access"> + + <question> + + <para> + Can triggers access tables? + </para> + + </question> + + <answer> + + <para> + A trigger can access both old and new data in its own table. + Through a stored procedure, or a multi-table update or + delete statement, a trigger can also affect other tables. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-udfs"> + + <question> + + <para> + Can triggers call an external application through a UDF? + </para> + + </question> + + <answer> + + <para> + No, not at present. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-triggers-update-remote-tables"> + + <question> + + <para> + Is possible for a trigger to update tables on a remote + server? + </para> + + </question> + + <answer> + + <para> + Yes. A table on a remote server could be updated using the + <literal>FEDERATED</literal> storage engine. (See + <xref + linkend="federated-storage-engine"/>). + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-views"> + + <title>MySQL ¤t-series; FAQ — Views</title> + + <qandaset> + + <qandaentry id="faqs-views-docs"> + + <question> + + <para> + Where can I find documentation for MySQL Views? + </para> + + </question> + + <answer> + + <para> + See <xref linkend="views"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-views-forum"> + + <question> + + <para> + Is there a discussion forum for MySQL Views? + </para> + + </question> + + <answer> + + <para> + Yes. See + <ulink + url="http://forums.mysql.com/list.php?100" + >http://forums.mysql.com/list.php?100</ulink> + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-views-alter-underlying-table"> + + <question> + + <para> + What happens to a view if an underlying table is dropped or + renamed? + </para> + + </question> + + <answer> + + <para> + After a view has been created, it is possible to drop or + alter a table or view to which the definition refers. To + check a view definition for problems of this kind, use the + <literal>CHECK TABLE</literal> statement. (See + <xref + linkend="check-table"/>.) + </para> + + </answer> + + </qandaentry> + + <qandaentry> + + <question> + + <para> + Does MySQL ¤t-series; have table snapshots? + </para> + + </question> + + <answer> + + <para> + No. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-views-materialized"> + + <question> + + <para> + Does MySQL ¤t-series; have materialized views? + </para> + + </question> + + <answer> + + <para> + No. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-views-insert-based-joins"> + + <question> + + <para> + Can you insert into views that are based on joins? + </para> + + </question> + + <answer> + + <para> + It is possible, provided that your <literal>INSERT</literal> + statement has a column list that makes it clear there's only + one table involved. + </para> + + <para> + You <emphasis>cannot</emphasis> insert into multiple tables + with a single insert on a view. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-information-schema"> + + <title>MySQL 5.0 FAQ — <literal>INFORMATION_SCHEMA</literal></title> + + <qandaset> + + <qandaentry id="faqs-information-schema-docs"> + + <question> + + <para> + Where can I find documentation for the MySQL + <literal>INFORMATION_SCHEMA</literal> database? + </para> + + </question> + + <answer> + + <para> + See <xref linkend="information-schema"/> + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-information-schema-forum"> + + <question> + + <para> + Is there a discussion forum for + <literal>INFORMATION_SCHEMA</literal>? + </para> + + </question> + + <answer> + + <para> + See + <ulink url="http://forums.mysql.com/list.php?101" + >http://forums.mysql.com/list.php?101</ulink>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-information-schema-spec"> + + <question> + + <para> + Where can I find the ANSI SQL 2003 specification for + <literal>INFORMATION_SCHEMA</literal>? + </para> + + </question> + + <answer> + + <para> + Unfortunately, the official specifications are not freely + available. (ANSI makes them available for purchase.) + However, there are books available — such as + <citetitle>SQL-99 Complete, Really</citetitle> by Peter + Gulutzan and Trudy Pelzer — which give a comprehensive + overview of the standard, including + <literal>INFORMATION_SCHEMA</literal>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-information-schema-data-dictionary"> + + <question> + + <para> + What is the difference between the Oracle Data Dictionary + and MySQL's <literal>INFORMATION_SCHEMA</literal>? + </para> + + </question> + + <answer> + + <para> + Both Oracle and MySQL provide metadata in tables. However, + Oracle and MySQL use different table names and column names. + MySQL's implementation is more similar to those found in DB2 + and SQL Server, which also support + <literal>INFORMATION_SCHEMA</literal> as defined in the SQL + standard. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-information-schema-modify-tables"> + + <question> + + <para> + Can I add to or otherwise modify the tables found in the + <literal>INFORMATION_SCHEMA</literal> database? + </para> + + </question> + + <answer> + + <para> + No. Since applications may rely on a certain standard + structure, this should not be modified.For this reason, + <emphasis>MySQL AB cannot support bugs or other issues which + result from modifying <literal>INFORMATION_SCHEMA</literal> + tables or data</emphasis>. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faqs-migration"> + + <title>MySQL ¤t-series; FAQ — Migration</title> + + <qandaset> + + <qandaentry id="faqs-migration-docs"> + + <question> + + <para> + Where can I find information on how to migrate from MySQL + &previous-series; to MySQL ¤t-series;? + </para> + + </question> + + <answer> + + <para> + For detailed upgrade information, see + <xref linkend="upgrade"/>. We recommend that you do not skip + a major version when upgrading, but rather complete the + process in steps, upgrading from one major version to the + next in each step. This may seem more complicated, but it + will you save time and trouble — if you encounter + problems during the upgrade, their origin will be easier to + identify, either by you or — if you have a MySQL + Network subscription — by MySQL support. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faqs-migration-storage-engines"> + + <question> + + <para> + How has storage engine (table type) support changed in MySQL + ¤t-series; from previous versions? + </para> + + </question> + + <answer> + + <para> + Storage engine support has changed as follows: + + <itemizedlist> + + <listitem> + <para> + Support for <literal>ISAM</literal> tables was removed + in MySQL 5.0 and you should now use the + <literal>MyISAM</literal> storage engine in place of + <literal>ISAM</literal>. To convert a table + <replaceable>tblname</replaceable> from + <literal>ISAM</literal> to <literal>MyISAM</literal>, + simply issue a statement such as this one: + </para> + +<programlisting>ALTER TABLE <replaceable>tblname</replaceable> ENGINE=MYISAM;</programlisting> + </listitem> + + <listitem> + <para> + Internal <literal>RAID</literal> for + <literal>MyISAM</literal> tables was also removed in + MySQL 5.0. This was formerly used to allow large + tables in filesystems that did not support filesizes + greater than 2GB. All modern filesystems allow for + larger tables; in addition, there are now other + solutions such as <literal>MERGE</literal> tables and + views. + </para> + </listitem> + + <listitem> + <para> + The <literal>VARCHAR</literal> column type now retains + trailing spaces in all storage engines. + </para> + </listitem> + + <listitem> + <para> + <literal>MEMORY</literal> tables (formerly known as + <literal>HEAP</literal> tables) can also contain + <literal>VARCHAR</literal> columns. + </para> + </listitem> + + </itemizedlist> + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + + <section id="faq-security"> + + <title>MySQL ¤t-series; FAQ - Security</title> + + <qandaset> + + <qandaentry id="faq-security-ssl-support"> + + <question> + + <para> + Does MySQL ¤t-series; have native support for SSL? + </para> + + </question> + + <answer> + + <para> + Most ¤t-series; binaries have support for SSL + connections between the client and server. We can't + currently build with the new YaSSL library everywhere, as + it's still quite new and does not compile on all platforms + yet. See <xref linkend="secure-connections"/>. + </para> + + <para> + You can also tunnel a connection via SSH, if (for instance) + if the client application doesn't support SSL connections. + For an example, see <xref linkend="windows-and-ssh"/>. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faq-security-built-in-ssl"> + + <question> + + <para> + Is SSL support be built into MySQL binaries, or must I + recompile the binary myself to enable it? + </para> + + </question> + + <answer> + + <para> + Most ¤t-series; binaries have SSL enabled for + client-server connections thsat are secured, authenticated, + or both. However, the YaSSL library currently does not + compile on all platforms. See + <xref linkend="secure-connections"/>, for a complete listing + of supported and unsupported platforms. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faq-security-ldap"> + + <question> + + <para> + Does MySQL ¤t-series; have built-in authentication + against LDAP directories? + </para> + + </question> + + <answer> + + <para> + No. Support for external authentication methods is on the + MySQL roadmap as a <quote>rolling feature</quote>, which + means that we plan to implement it in the future, but we + have not yet determined when this will be done. + </para> + + </answer> + + </qandaentry> + + <qandaentry id="faq-security-roles"> + + <question> + + <para> + Does MySQL ¤t-series; include support for Roles Based + Access Control (RBAC)? + </para> + + </question> + + <answer> + + <para> + No. Support for roles is on the MySQL roadmap as a + <quote>rolling feature</quote>, which means that we plan to + implement it in the future, but we have not yet determined + when this will be done. + </para> + + </answer> + + </qandaentry> + + </qandaset> + + </section> + +</chapter>
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| • svn commit - mysqldoc@docsrva: r3693 - trunk/refman-5.0 | jon | 21 Oct |
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