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SQLITE3_STMT_READONLY(3)   Library Functions Manual   SQLITE3_STMT_READONLY(3)

NAME
     sqlite3_stmt_readonly - Determine If An SQL Statement Writes The Database

SYNOPSIS
     int
     sqlite3_stmt_readonly(sqlite3_stmt *pStmt);

DESCRIPTION
     The sqlite3_stmt_readonly(X) interface returns true (non-zero) if and
     only if the prepared statement X 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:


     SELECT eval('DELETE FROM t1') FROM t2;


     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.  The
     sqlite3_stmt_readonly() interface returns true for BEGIN since BEGIN
     merely sets internal flags, but the BEGIN IMMEDIATE and BEGIN EXCLUSIVE
     commands do touch the database and so sqlite3_stmt_readonly() returns
     false for those commands.

SEE ALSO
     sqlite3_create_function(3), sqlite3_stmt(3), sqlite3_exec(3)

NetBSD 8.0                      March 11, 2017                      NetBSD 8.0