bk commit - mysqldoc tree (paul:1.2517)

[paul]

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ChangeSet
  1.2517 04/12/21 10:21:02 paul@stripped +1 -0
  manual.texi:
    Add some views information.

  Docs/manual.texi
    1.2280 04/12/21 10:20:48 paul@stripped +70 -13
    Add some views information.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	paul
# Host:	frost.snake.net
# Root:	/Volumes/frost2/MySQL/bk/mysqldoc

--- 1.2279/Docs/manual.texi	2004-12-21 09:25:49 -06:00
+++ 1.2280/Docs/manual.texi	2004-12-21 10:20:48 -06:00
@@ -57381,8 +57381,67 @@
 This statement creates a new view, or replaces an existing one if the
 @code{OR REPLACE} clause is given. The @var{select_statement} is a
 @code{SELECT} statement that provides the definition of the view.
-The optional column list can be given to define explicit names for the
-view columns.
+The statement can select from base tables or other views.
+
+A view belongs to a database.  By default, a new view is created in the
+current database.  To create the view explicitly in a given database,
+specify the name as @var{db_name.view_name} when you create it.
+
+@example
+mysql> CREATE VIEW test.v AS SELECT * FROM t;
+@end example
+
+Tables and views share the same namespace within a database, so a database
+cannot contain a table and a view that have the same name.
+
+Views must have unique column names with no duplicates, just like base
+tables.  By default, the names of the columns retrieved by the @code{SELECT}
+statement are used for the view column names.  To define explicit names for
+the view columns, the optional column list can be given.  In this case, the
+number of names in @var{column_list} must be the same as the number of
+columns retrieved by the @code{SELECT} statement.
+
+Columns retrieved by the @code{SELECT} statement can be simple references to
+table columns. They can also be expressions that use operators, functions,
+constant values, and so forth.
+
+@c TODO: however, use of anything othe than simple column references
+@c makes view not updatable. Updatable views must select only table columns.
+
+A view can refer to columns of tables or views in other databases by
+qualifying the table or view name with the proper database name.
+
+A view definition is subject to the following constraints:
+
+@itemize @bullet
+
+@item
+The @code{SELECT} statement cannot contain a subquery in the @code{FROM}
+clause.
+
+@item
+The @code{SELECT} statement cannot refer to user variables.
+
+@item
+Within a stored procedure, the definition cannot refer to procedure
+parameters.
+
+@item
+Any table or view referred to in the definition must exist.  However, after
+a view has been created, it is possible to drop a table or view that the
+definition refers to.
+@c TODO: add the following when CHECK VIEW gets pushed
+@c To check a view definition for problems of this kind, use the
+@c @code{CHECK VIEW} statement.
+
+@item
+The definition cannot refer to a @code{TEMPORARY} table, and you cannot
+create a @code{TEMPORARY} view.
+
+@item
+You cannot associate a trigger with a view.
+
+@end itemize
 
 @c TODO: need to describe ALGORITHM clause
 
@@ -57410,14 +57469,6 @@
 +------+-------+-------+
 @end example
 
-By default, the view is in the current database. To create
-the view explicitly in a given database, specify the name as
-@var{db_name.view_name} when you create it.
-
-@example
-mysql> CREATE VIEW test.v AS SELECT * FROM t;
-@end example
-
 In a @code{WITH CHECK OPTION} clause for an updatable view, the @code{LOCAL}
 and @code{CASCADED} keywords determine the scope of check testing when the
 view is defined in terms of another view.  @code{LOCAL} keyword restricts
@@ -60540,9 +60591,11 @@
 SHOW TABLE STATUS [FROM @var{db_name}] [LIKE '@var{pattern}']
 @end example
 
-@code{SHOW TABLE STATUS} (new in MySQL 3.23) works likes @code{SHOW
-TABLE}, but provides a lot of information about each table. You can
-also get this list using the @command{mysqlshow --status @var{db_name}} command.
+@code{SHOW TABLE STATUS} works likes @code{SHOW TABLE}, but provides a lot
+of information about each table. You can also get this list using the
+@command{mysqlshow --status @var{db_name}} command.  This statement was
+added in MySQL 3.23.  As of MySQL 5.0.1, it also displays information about
+views.
 
 @code{SHOW TABLE STATUS} returns the following fields:
 
@@ -60630,6 +60683,10 @@
 @code{Max_data_length}, and @code{Index_length} values approximate the
 actual amount of allocated memory. The allocation algorithm reserves memory
 in large amounts to reduce the number of allocation operations.
+
+For views, all the fields displayed by @code{SHOW TABLE STATUS} are
+@code{NULL} except that @code{Name} indicates the view name and @code{Comment}
+says @code{view}.
 
 
 @node SHOW TABLES, SHOW VARIABLES, SHOW TABLE STATUS, SHOW