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/*
** 2007 May 7
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file defines various limits of what SQLite can process.
**
** @(#) $Id$
*/
/*
** The maximum length of a TEXT or BLOB in bytes. This also
** limits the size of a row in a table or index.
**
** The hard limit is the ability of a 32-bit signed integer
** to count the size: 2^31-1 or 2147483647.
*/
/*
** This is the maximum number of
**
** * Columns in a table
** * Columns in an index
** * Columns in a view
** * Terms in the SET clause of an UPDATE statement
** * Terms in the result set of a SELECT statement
** * Terms in the GROUP BY or ORDER BY clauses of a SELECT statement.
** * Terms in the VALUES clause of an INSERT statement
**
** The hard upper limit here is 32676. Most database people will
** tell you that in a well-normalized database, you usually should
** not have more than a dozen or so columns in any table. And if
** that is the case, there is no point in having more than a few
** dozen values in any of the other situations described above.
*/
/*
** The maximum length of a single SQL statement in bytes.
**
** It used to be the case that setting this value to zero would
** turn the limit off. That is no longer true. It is not possible
** to turn this limit off.
*/
/*
** The maximum depth of an expression tree. This is limited to
** some extent by SQLITE_MAX_SQL_LENGTH. But sometime you might
** want to place more severe limits on the complexity of an
** expression.
**
** A value of 0 used to mean that the limit was not enforced.
** But that is no longer true. The limit is now strictly enforced
** at all times.
*/
/*
** The maximum number of terms in a compound SELECT statement.
** The code generator for compound SELECT statements does one
** level of recursion for each term. A stack overflow can result
** if the number of terms is too large. In practice, most SQL
** never has more than 3 or 4 terms. Use a value of 0 to disable
** any limit on the number of terms in a compount SELECT.
*/
/*
** The maximum number of opcodes in a VDBE program.
** Not currently enforced.
*/
/*
** The maximum number of arguments to an SQL function.
*/
/*
** The maximum number of in-memory pages to use for the main database
** table and for temporary tables. The SQLITE_DEFAULT_CACHE_SIZE
*/
/*
** The maximum number of attached databases. This must be between 0
** and 30. The upper bound on 30 is because a 32-bit integer bitmap
** is used internally to track attached databases.
*/
/*
** The maximum value of a ?nnn wildcard that the parser will accept.
*/
/* Maximum page size. The upper bound on this value is 32768. This a limit
** imposed by the necessity of storing the value in a 2-byte unsigned integer
** and the fact that the page size must be a power of 2.
*/
/*
** The default size of a database page.
*/
/*
** Ordinarily, if no value is explicitly provided, SQLite creates databases
** with page size SQLITE_DEFAULT_PAGE_SIZE. However, based on certain
** device characteristics (sector-size and atomic write() support),
** SQLite may choose a larger value. This constant is the maximum value
** SQLite will choose on its own.
*/
/*
** Maximum number of pages in one database file.
**
** This is really just the default value for the max_page_count pragma.
** This value can be lowered (or raised) at run-time using that the
** max_page_count macro.
*/
/*
** Maximum length (in bytes) of the pattern in a LIKE or GLOB
** operator.
*/