删除 SQLite 中的数据答案

【问题标题】：Delete data in SQLite删除 SQLite 中的数据
【发布时间】：2013-06-20 15:24:17
【问题描述】：

我想从数据库中删除记录，

我在 file.h 中定义了数据库，在 file.m 中定义了插入数据和读取数据，它可以工作，但删除不起作用。

这是文件.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;
}

在文件.m中

对于路径：

    -(NSString *)dataFilePath {
    NSArray * myPaths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory,NSUserDomainMask, YES); NSString * myDocPath = [myPaths objectAtIndex:0];
    NSString *filename = [myDocPath stringByAppendingPathComponent:DATA_FILE];
    return filename;

供阅读：

   -(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;
}

这是为了保存：

-(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);

}

但我没有删除数据的想法，有人可以帮我吗？

【问题讨论】：

标签： sql objective-c sqlite sql-delete

【解决方案1】：

你想删除所有选择的记录矿石

-(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 "您的查询是针对所有记录还是选中"

【讨论】：

选中的记录，如果可能在 - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
请解释更多..我无法理解..!!
如何在评论中写代码？？因为我有很多字符，所以我不能使用堆栈溢出:(
好的 .. 使用需要使用其他地方，例如与保管箱共享您的文件并在此处共享下载链接...！！如果我的评论对您有帮助，请标记。
okokokok, denmsg.altervista.org/delete_from_sql.txt 这是我的解决方案，那么，我该如何标记您的评论？？

【解决方案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);
}

【讨论】：