Not Able To delete data from SQLITE Database - ios

Question

What am i doing wrong here?? i have three table in database, and i need to delete all data from them.
-(void)deleteAllDataFromTables
{
AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
NSLog(#"%#", appDelegate.databasePath);
int result = sqlite3_open([appDelegate.databasePath UTF8String], &db);
if(result == SQLITE_OK)
{
NSLog(#"deleteCalled");
const char *deleteData = "delete from CustomerNumberTable";
int outcome = sqlite3_prepare_v2(db, deleteData, -1, &statement, NULL);
if(outcome == SQLITE_OK)
{
int res = sqlite3_step(statement);
if(res == SQLITE_DONE)
{
NSLog(#"deleted from Customer Table");
}
else
{
NSLog(#"not able to execute step statement");
}
}
else
{
NSLog(#"not deleted from Customer Table");
NSLog(#"the error is %s", sqlite3_errmsg(db));
}
sqlite3_finalize(statement);
const char *deleteData2 = "delete from KeyCodeTable";
int outcome2 = sqlite3_prepare_v2(db, deleteData2, -1, &statement, NULL);
if(outcome2 == SQLITE_OK)
{
int res = sqlite3_step(statement);
if(res == SQLITE_DONE)
{
NSLog(#"deleted from KeyCodeTable");
}
else
{
NSLog(#"not able to execute step statement");
}
}
else
{
NSLog(#"not deleted from KeyCodeTable");
NSLog(#"the error is %s", sqlite3_errmsg(db));
}
sqlite3_finalize(statement);
const char *deleteData3 = "delete from SRNumberTable";
int outcome3 = sqlite3_prepare_v2(db, deleteData3, -1, &statement, NULL);
if(outcome3 == SQLITE_OK)
{
int res = sqlite3_step(statement);
if(res == SQLITE_DONE)
{
NSLog(#"deleted from SRNumberTable");
}
else
{
NSLog(#"not able to execute step statement");
}
}
else
{
NSLog(#"not deleted from SRNumberTable");
NSLog(#"the error is %s", sqlite3_errmsg(db));
}
sqlite3_finalize(statement);
}
else
{
NSLog(#"Not able to open database for deleting");
}
}
On console, i am getting
Application[54974:a0b] deleteCalled
2014-01-03 16:12:55.442 Application[54974:a0b] deleted from Customer Table
2014-01-03 16:12:55.443 Application[54974:a0b] deleted from KeyCodeTable
2014-01-03 16:12:55.445 Application[54974:a0b] deleted from SRNumberTable
But when i am opening the database in on mac, the data is intact there..!! What is wrong with my code?? why isn't the data getting deleted??

Answer 1

I think you are copying your database from bundle to documents directory. So, the updated database will be present in documents directory. You seems to look the database from your workspace which is never going to be of updated one.

Answer 2

Your code opens database with sqlite3_open(), but does not close it using sqlite3_close(). This means that your database is probably still in open transaction, and quite possibly has 2 files: one is main database.db, and journal file database.db-journal which contains uncommitted intent to delete your tables.
You should make sure that your application closes database before you copy database file from the device to the host. At the very least, copy both main database AND journal file as one set. It is still likely to have consistency issues, but you should see your changes.

Answer 3

Try instead of sqlite3_prepare_v2 to sqlite3_exec. This working fine for me.
Just Ref:
char *errMsg;
const char *dbPath = [databasePath UTF8String];
if (sqlite3_open(dbPath, &database) == SQLITE_OK) {
NSLog(#"Db OPened ");
NSString *queryLists = [NSString stringWithFormat:#"delete from Table_name"];
const char *query_stmt = [queryLists UTF8String];
if (sqlite3_exec(database, query_stmt, NULL, NULL, &errMsg)
!= SQLITE_OK){
NSLog(#"Error %s", errMsg);
NSLog(#"Table Not Deleted");
}
}

Answer 4

1st thing Don't write same functionality code repeatedly in place create one function that delete all data from given table name,
2nd make sure you are looking at correct sqlite file in mac.
look this,
-(void)deleteAllData
{
[self deleteTable: CustomerNumberTable];
[self deleteTable: SRNumberTable];
[self deleteTable: KeyCodeTable];
}
-(void)deleteTable:(NSString *)table;
{
const char *dbpath=[appDelegate.databasePath UTF8String];
if (sqlite3_open(dbpath, &dtdb)==SQLITE_OK)
{
sqlite3_stmt *stmt;
const char *qry=[[NSString stringWithFormat:#"delete from %#",table] UTF8String];
sqlite3_prepare_v2(dtdb, qry, -1, &stmt, NULL);
if (sqlite3_step(stmt)==SQLITE_DONE)
{
NSLog(#"%# Table data deleted",table);
}
sqlite3_finalize(stmt);
sqlite3_close(dtdb);
}
}