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我正在使用此代码从 Sqlite3 数据库中删除行，但它不起作用，插入、更新、选择查询工作正常，但删除语句在我的代码中不起作用

 -(void)delete{

        str=title.text;
        sqlite3_stmt *selectstmt;
        if (sqlite3_open([path UTF8String], &database) == SQLITE_OK) {
            NSString *deleteSQL = [NSString stringWithFormat: @"delete from ToDo where title=\"%@\"",str];
            NSLog(@"%@",deleteSQL);
            const char *sql = [deleteSQL UTF8String];
            sqlite3_prepare_v2(database,sql, -1, &selectstmt, NULL); 
            if(sqlite3_prepare_v2(database, sql, -1, &selectstmt, NULL) == SQLITE_OK) 
               NSLog(@"success");
            else
              NSAssert1(0, @"Error while creating delete statement. '%s'", sqlite3_errmsg(database));            
            }
            sqlite3_finalize(selectstmt);
            sqlite3_close(database);
        }

我究竟做错了什么？

4

3 回答 3

3

嗨看看它。

我认为您在传递参数时做错了。

编辑：

    str=title.text;
    [self openDatabase];//Logic to open database goes here
    sqlite3_stmt *stmt=nil;
    BOOL status=FALSE;

    NSString *deleteSQL = [NSString stringWithFormat: @"delete from ToDo where title='%@'",str];
    NSLog(@"%@",deleteSQL);
    const char *sql = [deleteSQL UTF8String];


   //const char *sql ="delete from ToDo where title='%@'";

   if(sqlite3_prepare_v2(db, sql, -1, &stmt, NULL) == SQLITE_OK)
   {
         sqlite3_bind_text(stmt, 1, [_testId UTF8String], -1, SQLITE_STATIC);

         if(SQLITE_DONE != sqlite3_step(stmt))
               { 
                 NSLog(@"Error while Deleting");
               }


    }
    sqlite3_finalize(stmt);
  [self closeDatabase];//Logic to close database goes here
于 2012-10-03T05:24:17.477 回答
3

您可以使用以下代码从 sqlite 数据库中删除特定记录：-

NSDictionary *d =(NSDictionary *) [YourMutableArray objectAtIndex:0];
NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDir = [path objectAtIndex:0];
NSString *dbPath =[documentsDir stringByAppendingPathComponent:@"db.sqlite"];
sqlite3_open([dbPath UTF8String], &database);

if(deleteStmt == nil) 
{

    NSString *deleteStatementNS = [NSString stringWithFormat:
                                   @"delete from tbl_postoffice where type = '%@'",
                                   urusniqIDentifire];
    const char *sql = [deleteStatementNS UTF8String];

    //const char *sql ="delete from tbl_todo where type = yourDbfildeRecored";
    if(sqlite3_prepare_v2(database, sql, -1, &deleteStmt, NULL) != SQLITE_OK)
        NSAssert1(0, @"Error while creating delete statement. '%s'", sqlite3_errmsg(database));
}

//When binding parameters, index starts from 1 and not zero.
sqlite3_bind_text(deleteStmt, 1, [[d valueForKey:@"type"] UTF8String], -1, SQLITE_TRANSIENT);
if (SQLITE_DONE != sqlite3_step(deleteStmt)) 
    NSAssert1(0, @"Error while deleting. '%s'", sqlite3_errmsg(database));

sqlite3_reset(deleteStmt);

希望它对你有帮助

于 2012-10-03T05:43:09.677 回答
0

是的@jason Coco 是正确的，您已经准备了两次声明，并且在准备声明之后也没有调用 step ..尝试在准备之后调用它：

if (sqlite3_step(selectstmt) == SQLITE_DONE)
{
    NSLog(@"success");
}
于 2012-10-03T05:22:35.763 回答