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/**
* \file select.c
*
* \brief Low level SQLite database functions.
*
* This program is free software under the GNU General Public License
* (>=v2). Read the file COPYING that comes with GRASS for details.
*
* \author Radim Blazek
* \author Support for multiple connections by Markus Metz
*
* \date 2005-2011
*/
#include <stdlib.h>
#include <grass/dbmi.h>
#include <grass/gis.h>
#include <grass/glocale.h>
#include "globals.h"
#include "proto.h"
/**
* \fn int db__driver_open_select_cursor (dbString *sel, dbCursor *dbc, int
* mode)
*
* \brief Open SQLite cursor for select.
*
* \param[in] sel
* \param[in,out] dbc
* \param[in] mode
* \return int DB_FAILED on error; DB_OK on success
*/
int db__driver_open_select_cursor(dbString *sel, dbCursor *dbc, int mode)
{
cursor *c;
dbTable *table;
char *str;
const char *rest;
int ret;
/* allocate cursor */
c = alloc_cursor();
if (c == NULL)
return DB_FAILED;
db_set_cursor_mode(dbc, mode);
db_set_cursor_type_readonly(dbc);
/* \ must be escaped, see explanation in db_driver_execute_immediate() */
str = G_str_replace(db_get_string(sel), "\\", "\\\\");
G_debug(3, "Escaped SQL: %s", str);
/* SQLITE bug?
* If the database schema has changed, sqlite can prepare a statement,
* but sqlite can not step, the statement needs to be prepared anew again */
while (1) {
ret = sqlite3_prepare(sqlite, str, -1, &(c->statement), &rest);
if (ret != SQLITE_OK) {
db_d_append_error("%s\n%s\n%s", _("Error in sqlite3_prepare():"),
db_get_string(sel),
(char *)sqlite3_errmsg(sqlite));
db_d_report_error();
return DB_FAILED;
}
ret = sqlite3_step(c->statement);
/* get real result code */
ret = sqlite3_reset(c->statement);
if (ret == SQLITE_SCHEMA) {
sqlite3_finalize(c->statement);
/* try again */
}
else if (ret != SQLITE_OK) {
db_d_append_error("%s\n%s", _("Error in sqlite3_step():"),
(char *)sqlite3_errmsg(sqlite));
db_d_report_error();
sqlite3_finalize(c->statement);
return DB_FAILED;
}
else
break;
}
if (str)
G_free(str);
if (describe_table(c->statement, &table, c) == DB_FAILED) {
db_d_append_error("%s\n%s", _("Unable to describe table:"),
(char *)sqlite3_errmsg(sqlite));
db_d_report_error();
return DB_FAILED;
}
c->nrows = -1;
c->row = -1;
/* record table with dbCursor */
db_set_cursor_table(dbc, table);
/* set dbCursor's token for my cursor */
db_set_cursor_token(dbc, c->token);
return DB_OK;
}
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