3

大家好

我需要在现有表中添加一列，所以如何通过 obj c 更改 sqlite 数据库中的表，我正在使用以下代码以相同的方式将数据插入表中如何编写更新表方法

- (void) InsertRecord {


if(addStmt == nil) {
    const char *sql = "insert into tbl_Users(FirstName,MiddleName) Values(?,?)";
    if(sqlite3_prepare_v2(database, sql, -1, &addStmt, NULL) != SQLITE_OK)
        NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database));
}

sqlite3_bind_text(addStmt, 1, [strFirstName UTF8String], -1, SQLITE_TRANSIENT);
sqlite3_bind_text(addStmt, 2, [strMiddleName UTF8String], -1, SQLITE_TRANSIENT);
//sqlite3_bind_text(addStmt, 3, [strLogin UTF8String], -3, SQLITE_TRANSIENT);


if(SQLITE_DONE != sqlite3_step(addStmt))
    NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(database));
else
    //SQLite provides a method to get the last primary key inserted by using sqlite3_last_insert_rowid
    //productID = sqlite3_last_insert_rowid(database);

//Reset the add statement.
sqlite3_reset(addStmt);

}

任何人都可以帮助我,,thanx提前

4

1 回答 1

18

这可能有点用处。头文件

NSString *databasePath;

.m File //调用这些方法

    [self checkAndCreateDB ];
    [self alterDB];

-(void)checkAndCreateDB {
    NSString* databaseName = @"MasterDB.sqlite";
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [documentPaths objectAtIndex:0];
    databasePath = [documentsDir stringByAppendingPathComponent:databaseName];
    BOOL success1;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    success1 = [fileManager fileExistsAtPath:databasePath];
    if(success1) return;
    NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];
    [fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
}

-(void) alterDB{
    sqlite3 *database;
    sqlite3_stmt *statement; 
    if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
    {

        NSString *updateSQL = [NSString stringWithFormat: @"ALTER TABLE User ADD COLUMN testColumn TEXT"];
        const char *update_stmt = [updateSQL UTF8String];
        sqlite3_prepare_v2(database, update_stmt, -1, &statement, NULL);

        if(sqlite3_step(statement)==SQLITE_DONE) 
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"DB altered" message:@"Success" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];    
            [alert show];
            [alert release];
            alert=nil;

        }
        else 
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"DB Updation" message:@"DB not Altered" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];   
            [alert show];
            [alert release];
            alert=nil;
        }   
        // Release the compiled statement from memory
        sqlite3_finalize(statement);    
        sqlite3_close(database);
    }
}
于 2011-05-02T04:22:37.733 回答