SQLite: Check-in [9c19b7ae]

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Overview

Comment:	Update the sqlite3_stmt_readonly() interface so that its output is well-defined for all prepared statements, and so that it gives the correct result for VACUUM.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| trunk
Files:	files \| file ages \| folders
SHA1:	9c19b7ae3542fd1fac692b4471f1839b22685c76
User & Date:	drh 2010-12-08 18:30:20

Context

2010-12-09
18:55		Mention the SQLITE_DEFAULT_WAL_AUTOCHECKPOINT compile-time option in the documentation for the sqlite3_wal_autocheckpoint() interface. (check-in: 5a52dd59 user: drh tags: trunk)
2010-12-08
18:30		Update the sqlite3_stmt_readonly() interface so that its output is well-defined for all prepared statements, and so that it gives the correct result for VACUUM. (check-in: 9c19b7ae user: drh tags: trunk)
03:28		The command-line shell ignore errors in sqlite3_close() when shutting down. (check-in: 925332c3 user: drh tags: trunk)

Changes

Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/sqlite.h.in.

** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
*/
const char *sqlite3_sql(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Determine If An SQL Statement Writes The Database
**
** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
** the [prepared statement] X is [SELECT] statement and false (zero) if
** X is an [INSERT], [UPDATE], [DELETE], CREATE, DROP, [ANALYZE],
** [ALTER], or [REINDEX] statement.
** If X is a NULL pointer or any other kind of statement, including but
** not limited to [ATTACH], [DETACH], [COMMIT], [ROLLBACK], [RELEASE],
** [SAVEPOINT], [PRAGMA], or [VACUUM] the result of sqlite3_stmt_readonly(X) is
** undefined.

















*/
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Dynamically Typed Value Object
** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
**








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** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
*/
const char *sqlite3_sql(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Determine If An SQL Statement Writes The Database
**
** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 
** and only if the [prepared statement] X is makes no direct changes to
** the content of the database file.
**
** Note that [application-defined SQL functions] or
** [virtual tables] might change the database indirectly as a side effect.  
** ^(For example, if an application defines a function "eval()" that 
** calls [sqlite3_exec()], then the following SQL statement would
** change the database file through side-effects:
**
** <blockquote><pre>
**    SELECT eval('DELETE FROM t1') FROM t2;
** </pre></blockquote>
**
** But because the [SELECT] statement does not change the database file
** directly, sqlite3_stmt_readonly() would still return true.)^
**
** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
** since the statements themselves do not actually modify the database but
** rather they control the timing of when other statements modify the 
** database.  ^The [ATTACH] and [DETACH] statements also cause
** sqlite3_stmt_readonly() to return true since, while those statements
** change the configuration of a database connection, they do not make 
** changes to the content of the database files on disk.
*/
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

/*
** CAPI3REF: Dynamically Typed Value Object
** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
**

Changes to src/vdbeaux.c.

  p->readOnly = 1;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    pOp->opflags = sqlite3OpcodeProperty[opcode];
    if( opcode==OP_Function || opcode==OP_AggStep ){
      if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
    }else if( opcode==OP_Transaction && pOp->p2!=0 ){
      p->readOnly = 0;
#ifndef SQLITE_OMIT_VIRTUALTABLE
    }else if( opcode==OP_VUpdate ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }else if( opcode==OP_VFilter ){
      int n;
      assert( p->nOp - i >= 3 );

  p->readOnly = 1;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    pOp->opflags = sqlite3OpcodeProperty[opcode];
    if( opcode==OP_Function || opcode==OP_AggStep ){
      if( pOp->p5>nMaxArgs ) nMaxArgs = pOp->p5;
    }else if( (opcode==OP_Transaction && pOp->p2!=0) || opcode==OP_Vacuum ){
      p->readOnly = 0;
#ifndef SQLITE_OMIT_VIRTUALTABLE
    }else if( opcode==OP_VUpdate ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }else if( opcode==OP_VFilter ){
      int n;
      assert( p->nOp - i >= 3 );