sqlite: can i do select statement while looping through another select statement
In my iPhone app, I use a sqlite table to hold my data. While I'm looping through a select statement on one of the tables, I want to do another select 开发者_如何学编程(and update) statement on the same table in some conditions. It's pretty complicated to explain why I would want to do this, but I'm pretty sure I need to.
The problem is that when I loop through the outer while loop, if I call the inner select statement, it terminates the outer loop after that run, even if it has more rows in the sql statement. So is this impossible? Can I call a select statement while I'm looping through the sqlite3_step results on the same table? Here's some psuedo-code (in objective-c) to explain what I'm doing:
sqlite3_exec(database, "BEGIN", 0, 0, 0); // Begin Transaction
if (init_all_statement == nil)
{
const char *sql = "SELECT id, fullname FROM contact";
if (sqlite3_prepare_v2(database, sql, -1, &init_all_statement, NULL) != SQLITE_OK) {
NSAssert1(0, @"Error Test.m: failed with message '%s'.", sqlite3_errmsg(database));
}
}
while (sqlite3_step(init_all_statement) == SQLITE_ROW)
{
...
if (blah)
{
if (get_duplicate_rows == nil)
{
const char *sql = "SELECT id, fullname FROM contact where fullname = ?";
if (sqlite3_prepare_v2(database, sql, -1, &get_duplicate_rows, NULL) != SQLITE_OK) {
NSAssert1(0, @"Error Test.m: failed with message '%s'.", sqlite3_errmsg(database));
}
}
sqlite3_bind_text(get_duplicate_rows, 1, [contact_fullname UTF8String], -1, SQLITE_TRANSIENT);
while (sqlite3_step(get_duplicate_rows) == SQLITE_ROW)
{
...
}
sqlite3_reset(get_one_row);
}
}
Yes, it is possible, you only need to create a new statement to receive the new results
sqlite3_stmt *statement;
Cheers,
VFN
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