sqlite3.h

SQLite的VS2005封装

** <dd>This option specifies a static memory buffer that SQLite can use for
** scratch memory.  There are three arguments:  A pointer to the memory, the
** size of each scratch buffer (sz), and the number of buffers (N).  The sz
** argument must be a multiple of 16. The sz parameter should be a few bytes
** larger than the actual scratch space required due internal overhead.
** The first
** argument should point to an allocation of at least sz*N bytes of memory.
** SQLite will use no more than one scratch buffer at once per thread, so
** N should be set to the expected maximum number of threads.  The sz
** parameter should be 6 times the size of the largest database page size.
** Scratch buffers are used as part of the btree balance operation.  If
** The btree balancer needs additional memory beyond what is provided by
** scratch buffers or if no scratch buffer space is specified, then SQLite
** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd>
**
** <dt>SQLITE_CONFIG_PAGECACHE</dt>
** <dd>This option specifies a static memory buffer that SQLite can use for
** the database page cache.  There are three arguments: A pointer to the
** memory, the size of each page buffer (sz), and the number of pages (N).
** The sz argument must be a power of two between 512 and 32768.  The first
** argument should point to an allocation of at least sz*N bytes of memory.
** SQLite will use the memory provided by the first argument to satisfy its
** memory needs for the first N pages that it adds to cache.  If additional
** page cache memory is needed beyond what is provided by this option, then
** SQLite goes to [sqlite3_malloc()] for the additional storage space.
** The implementation might use one or more of the N buffers to hold 
** memory accounting information. </dd>
**
** <dt>SQLITE_CONFIG_HEAP</dt>
** <dd>This option specifies a static memory buffer that SQLite will use
** for all of its dynamic memory allocation needs beyond those provided
** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].
** There are three arguments: A pointer to the memory, the number of
** bytes in the memory buffer, and the minimum allocation size.  If
** the first pointer (the memory pointer) is NULL, then SQLite reverts
** to using its default memory allocator (the system malloc() implementation),
** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  If the
** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or
** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory
** allocator is engaged to handle all of SQLites memory allocation needs.</dd>
**
** <dt>SQLITE_CONFIG_MUTEX</dt>
** <dd>This option takes a single argument which is a pointer to an
** instance of the [sqlite3_mutex_methods] structure.  The argument specifies
** alternative low-level mutex routines to be used in place
** the mutex routines built into SQLite.</dd>
**
** <dt>SQLITE_CONFIG_GETMUTEX</dt>
** <dd>This option takes a single argument which is a pointer to an
** instance of the [sqlite3_mutex_methods] structure.  The
** [sqlite3_mutex_methods]
** structure is filled with the currently defined mutex routines.
** This option can be used to overload the default mutex allocation
** routines with a wrapper used to track mutex usage for performance
** profiling or testing, for example.</dd>
**
** <dt>SQLITE_CONFIG_LOOKASIDE</dt>
** <dd>This option takes two arguments that determine the default
** memory allcation lookaside optimization.  The first argument is the
** size of each lookaside buffer slot and the second is the number of
** slots allocated to each database connection.</dd>
**
** </dl>
*/
#define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
#define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
#define SQLITE_CONFIG_SERIALIZED    3  /* nil */
#define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
#define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
#define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
#define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
#define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
#define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
#define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
#define SQLITE_CONFIG_CHUNKALLOC   12  /* int threshold */
#define SQLITE_CONFIG_LOOKASIDE    13  /* int int */

/*
** CAPI3REF: Configuration Options {H10170} <S20000>
** EXPERIMENTAL
**
** These constants are the available integer configuration options that
** can be passed as the second argument to the [sqlite3_db_config()] interface.
**
** New configuration options may be added in future releases of SQLite.
** Existing configuration options might be discontinued.  Applications
** should check the return code from [sqlite3_db_config()] to make sure that
** the call worked.  The [sqlite3_db_config()] interface will return a
** non-zero [error code] if a discontinued or unsupported configuration option
** is invoked.
**
** <dl>
** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
** <dd>This option takes three additional arguments that determine the 
** [lookaside memory allocator] configuration for the [database connection].
** The first argument (the third parameter to [sqlite3_db_config()] is a
** pointer to a memory buffer to use for lookaside memory.  The first
** argument may be NULL in which case SQLite will allocate the lookaside
** buffer itself using [sqlite3_malloc()].  The second argument is the
** size of each lookaside buffer slot and the third argument is the number of
** slots.  The size of the buffer in the first argument must be greater than
** or equal to the product of the second and third arguments.</dd>
**
** </dl>
*/
#define SQLITE_DBCONFIG_LOOKASIDE    1001  /* void* int int */


/*
** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700>
**
** The sqlite3_extended_result_codes() routine enables or disables the
** [extended result codes] feature of SQLite. The extended result
** codes are disabled by default for historical compatibility considerations.
**
** INVARIANTS:
**
** {H12201} Each new [database connection] shall have the
**          [extended result codes] feature disabled by default.
**
** {H12202} The [sqlite3_extended_result_codes(D,F)] interface shall enable
**          [extended result codes] for the  [database connection] D
**          if the F parameter is true, or disable them if F is false.
*/
int sqlite3_extended_result_codes(sqlite3*, int onoff);

/*
** CAPI3REF: Last Insert Rowid {H12220} <S10700>
**
** Each entry in an SQLite table has a unique 64-bit signed
** integer key called the "rowid". The rowid is always available
** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
** names are not also used by explicitly declared columns. If
** the table has a column of type INTEGER PRIMARY KEY then that column
** is another alias for the rowid.
**
** This routine returns the rowid of the most recent
** successful INSERT into the database from the [database connection]
** in the first argument.  If no successful INSERTs
** have ever occurred on that database connection, zero is returned.
**
** If an INSERT occurs within a trigger, then the rowid of the inserted
** row is returned by this routine as long as the trigger is running.
** But once the trigger terminates, the value returned by this routine
** reverts to the last value inserted before the trigger fired.
**
** An INSERT that fails due to a constraint violation is not a
** successful INSERT and does not change the value returned by this
** routine.  Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
** and INSERT OR ABORT make no changes to the return value of this
** routine when their insertion fails.  When INSERT OR REPLACE
** encounters a constraint violation, it does not fail.  The
** INSERT continues to completion after deleting rows that caused
** the constraint problem so INSERT OR REPLACE will always change
** the return value of this interface.
**
** For the purposes of this routine, an INSERT is considered to
** be successful even if it is subsequently rolled back.
**
** INVARIANTS:
**
** {H12221} The [sqlite3_last_insert_rowid()] function returns the rowid
**          of the most recent successful INSERT performed on the same
**          [database connection] and within the same or higher level
**          trigger context, or zero if there have been no qualifying inserts.
**
** {H12223} The [sqlite3_last_insert_rowid()] function returns the
**          same value when called from the same trigger context
**          immediately before and after a ROLLBACK.
**
** ASSUMPTIONS:
**
** {A12232} If a separate thread performs a new INSERT on the same
**          database connection while the [sqlite3_last_insert_rowid()]
**          function is running and thus changes the last insert rowid,
**          then the value returned by [sqlite3_last_insert_rowid()] is
**          unpredictable and might not equal either the old or the new
**          last insert rowid.
*/
sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);

/*
** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600>
**
** This function returns the number of database rows that were changed
** or inserted or deleted by the most recently completed SQL statement
** on the [database connection] specified by the first parameter.
** Only changes that are directly specified by the INSERT, UPDATE,
** or DELETE statement are counted.  Auxiliary changes caused by
** triggers are not counted. Use the [sqlite3_total_changes()] function
** to find the total number of changes including changes caused by triggers.
**
** A "row change" is a change to a single row of a single table
** caused by an INSERT, DELETE, or UPDATE statement.  Rows that
** are changed as side effects of REPLACE constraint resolution,
** rollback, ABORT processing, DROP TABLE, or by any other
** mechanisms do not count as direct row changes.
**
** A "trigger context" is a scope of execution that begins and
** ends with the script of a trigger.  Most SQL statements are
** evaluated outside of any trigger.  This is the "top level"
** trigger context.  If a trigger fires from the top level, a
** new trigger context is entered for the duration of that one
** trigger.  Subtriggers create subcontexts for their duration.
**
** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does
** not create a new trigger context.
**
** This function returns the number of direct row changes in the
** most recent INSERT, UPDATE, or DELETE statement within the same
** trigger context.
**
** Thus, when called from the top level, this function returns the
** number of changes in the most recent INSERT, UPDATE, or DELETE
** that also occurred at the top level.  Within the body of a trigger,
** the sqlite3_changes() interface can be called to find the number of
** changes in the most recently completed INSERT, UPDATE, or DELETE
** statement within the body of the same trigger.
** However, the number returned does not include changes
** caused by subtriggers since those have their own context.
**
** SQLite implements the command "DELETE FROM table" without a WHERE clause
** by dropping and recreating the table.  (This is much faster than going
** through and deleting individual elements from the table.)  Because of this
** optimization, the deletions in "DELETE FROM table" are not row changes and
** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
** functions, regardless of the number of elements that were originally
** in the table.  To get an accurate count of the number of rows deleted, use
** "DELETE FROM table WHERE 1" instead.
**
** INVARIANTS:
**
** {H12241} The [sqlite3_changes()] function shall return the number of
**          row changes caused by the most recent INSERT, UPDATE,
**          or DELETE statement on the same database connection and
**          within the same or higher trigger context, or zero if there have
**          not been any qualifying row changes.
**
** {H12243} Statements of the form "DELETE FROM tablename" with no
**          WHERE clause shall cause subsequent calls to
**          [sqlite3_changes()] to return zero, regardless of the
**          number of rows originally in the table.
**
** ASSUMPTIONS:
**
** {A12252} If a separate thread makes changes on the same database connection
**          while [sqlite3_changes()] is running then the value returned
**          is unpredictable and not meaningful.
*/
int sqlite3_changes(sqlite3*);

/*
** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600>
**
** This function returns the number of row changes caused by INSERT,
** UPDATE or DELETE statements since the [database connection] was opened.
** The count includes all changes from all trigger contexts.  However,
** the count does not include changes used to implement REPLACE constraints,
** do rollbacks or ABORT processing, or DROP table processing.
** The changes are counted as soon as the statement that makes them is
** completed (when the statement handle is passed to [sqlite3_reset()] or
** [sqlite3_finalize()]).
**
** SQLite implements the command "DELETE FROM table" without a WHERE clause
** by dropping and recreating the table.  (This is much faster than going
** through and deleting individual elements from the table.)  Because of this
** optimization, the deletions in "DELETE FROM table" are not row changes and
** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()]
** functions, regardless of the number of elements that were originally
** in the table.  To get an accurate count of the number of rows deleted, use
** "DELETE FROM table WHERE 1" instead.
**
** See also the [sqlite3_changes()] interface.
**
** INVARIANTS:
**
** {H12261} The [sqlite3_total_changes()] returns the total number
**          of row changes caused by INSERT, UPDATE, and/or DELETE
**          statements on the same [database connection], in any
**          trigger context, since the database connection was created.
**
** {H12263} Statements of the form "DELETE FROM tablename" with no
**          WHERE clause shall not change t