Delete data in SQLite - sql

Question

I want to delete record from database,
I define in file.h the database, and in the file.m the insert data and read data it's work, but the delete was not work.
this is the file.h
#import "sqlite3.h"
#define DATA_FILE #"prova12"
#define TABLE_NAME #"password"
#define FIELDS_NAME_SID #"pass"
#define FIELDS_NAME_SNAME #"foto"
#define FIELDS_NAME_SCLASS #"studentClass"
#define FIELDS_NAME_PROVA #"provaClass"
{sqlite3 *db;
}
in the file.m
for the path:
-(NSString *)dataFilePath {
NSArray * myPaths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory,NSUserDomainMask, YES); NSString * myDocPath = [myPaths objectAtIndex:0];
NSString *filename = [myDocPath stringByAppendingPathComponent:DATA_FILE];
return filename;
for read:
-(NSMutableArray*)selectAll
{
NSMutableArray *list = [[NSMutableArray alloc] initWithObjects:nil];
NSString *filename = [self dataFilePath];
NSLog(#"%#",filename);
if (sqlite3_open([filename UTF8String], &db) != SQLITE_OK) {
sqlite3_close(db);
NSAssert(NO,#"no");
} else {
NSString *qsql = [NSString stringWithFormat: #"SELECT %# FROM %#", FIELDS_NAME_SID, TABLE_NAME];
NSLog(#"qui%#",qsql);
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(db, [qsql UTF8String], -1, &statement, NULL) == SQLITE_OK) {
sqlite3_bind_text(statement, 1, [inserisci.text UTF8String], -1, NULL);
while (sqlite3_step(statement) == SQLITE_ROW) {
char *field1 = (char *) sqlite3_column_text(statement, 0);
NSString *field1Str = [[NSString alloc] initWithUTF8String: field1];
//studentId.text = field1Str;
//[field1Str release];
[list addObject:field1Str];
NSLog(#"%d",list.count);
}
}
sqlite3_finalize(statement);
sqlite3_close(db);
}
return list;
}
and this for save:
-(IBAction) save {
NSString *filename = [self dataFilePath];
if (sqlite3_open([filename UTF8String], &db) != SQLITE_OK) {
sqlite3_close(db);
NSAssert(NO,#"no");
} else {
NSString *sqlStr = [NSString stringWithFormat: #"INSERT OR REPLACE INTO %# (%#, %#, %# ,%#) VALUES (?,?,?,?)",
TABLE_NAME, FIELDS_NAME_SID, FIELDS_NAME_SNAME, FIELDS_NAME_SCLASS, FIELDS_NAME_PROVA];
sqlite3_stmt *statement;
if (sqlite3_prepare_v2(db, [sqlStr UTF8String], -1, &statement, NULL) == SQLITE_OK) {
NSLog(#"quiiiiddddd %#", filename);
sqlite3_bind_text(statement, 1, [inserisci.text UTF8String], -1, NULL);
sqlite3_bind_text(statement, 2, [immagine UTF8String], -1, NULL);
sqlite3_bind_text(statement, 3, [inserisci.text UTF8String], -1, NULL);
sqlite3_bind_text(statement, 4, [inserisci.text UTF8String], -1, NULL);
if (sqlite3_step(statement) != SQLITE_DONE) {
NSAssert(0, #"no");
}
}
sqlite3_finalize(statement);
sqlite3_close(db);
}
but I don't have an idea to delete data, can anyone please help me?

Answer 1

you want to delete all record ore selected
-(bool)deleteEvent:(int)eventID
{
DBSettings *dbSettings = [[DBSettings alloc]init];
[dbSettings checkAndCreateDatabase];
DatabaseName=dbSettings.DBName;
DatabasePath=dbSettings.DBPath;
[dbSettings release];
sqlite3 *database;
if(sqlite3_open([DatabasePath UTF8String], &database) == SQLITE_OK)
{
const char *sqlStatement;
NSString *query = [NSString stringWithFormat:#"%#'%i'",kDeleteQuery,eventID];
//Convert NSString to char pointer for execution
sqlStatement=[query UTF8String];
if(sqlite3_prepare_v2(database, sqlStatement, -1, &deleteStmt, NULL) != SQLITE_OK)
NSAssert1(0, #"Error while creating add statement. '%s'", sqlite3_errmsg(database));
if(SQLITE_DONE != sqlite3_step(deleteStmt))
{
NSAssert1(0, #"Error while deleting data. '%s'", sqlite3_errmsg(database));
}
sqlite3_finalize(deleteStmt);
sqlite3_close(database);
return YES;
}
return NO;
}
kDeleteQuery "Is your query for all record or selected"

Answer 2

-(void)deleteDetails:(int *)detailId
{
if (sqlite3_open([filename UTF8String], &db) != SQLITE_OK)
{
sqlite3_close(db);
}
else
{
sqlite3_stmt *statement;
NSString *strSQL =[NSString stringWithFormat:#"DELETE FROM tablename WHERE id = %d", detailId];
mainSql = [strSQL UTF8String];
if(sqlite3_prepare_v2(db, mainSql , -1, &statement, NULL)==SQLITE_OK)
{
while(sqlite3_step(statement) == SQLITE_ROW)
{
NSLog(#"Records are deleted");
}
}
else
{
NSLog(#"Error : -------'%s'", sqlite3_errmsg(db));
}
}
sqlite3_reset(statement);
sqlite3_finalize(statement);
sqlite3_close(db);
}