如何将数据插入iPhone中的SQLite数据库 [英] How to insert data into a SQLite database in iPhone

问题描述

我是iPhone开发的新手。我想将某些数据插入到我的数据库中并检索它
并将其显示在表格中。我用表'user'创建了 Database data.sqlite 。该表有两个值，id（varchar）和name（varchar）。我通过插入用户值（'1'，'xxxx'）在表中插入了3行数据;在终端窗口。我创建了一个名为testDb的基于导航的应用程序。在 AppDelegate 中我有两种方法

I am new to iPhone development. I want to insert certain data into my database and retrieve it and display it in a table. I have created Database data.sqlite with table 'user'. The table has two values, id(varchar) and name(varchar). I have inserted 3 rows of data in the table via "insert into user value('1','xxxx');" in the terminal window. I have created a navigation based applicaton named "testDb". In AppDelegate I have two methods

- (void)createEditableCopyOfDatabaseIfNeeded {
    NSLog(@"Creating editable copy of database");
    // First, test for existence.
    BOOL success;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"data.sqlite"];
    success = [fileManager fileExistsAtPath:writableDBPath];
    if (success) return;
    // The writable database does not exist, so copy the default to the appropriate location.
    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"data.sqlite"];
    success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
    if (!success) {
        NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);
    }
}

和

+(sqlite3 *) getNewDBConnection{
    sqlite3 *newDBconnection;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"data.sqlite"];
    // Open the database. The database was prepared outside the application.
    if (sqlite3_open([path UTF8String], &newDBconnection) == SQLITE_OK) {
        NSLog(@"Database Successfully Opened :)");
    }
    else {
        NSLog(@"Error in opening database :(");
    }
    return newDBconnection;
}

在rootviewcontroller中

In rootviewcontroller

-(void)initializeTableData{
    sqlite3 *db=[DatabaseTestAppDelegate getNewDBConnection];
    sqlite3_stmt *statement=nil;
    const char *sql="select * from user";
    if (sqlite3_prepare_v2(db, sql, -1, &statement, NULL)!=SQLITE_OK)
        NSAssert1(0,@"error in preparing staement",sqlite3_errmsg(db));
    else {
        while(sqlite3_step(statement)==SQLITE_ROW)
            [tableData addObject:[NSString stringWithFormat:@"%s",(char*)sqlite3_column_text(statement,1)]];
    }
    sqlite3_finalize(statement);
}

- (void)viewDidLoad {
    [super viewDidLoad];
    tableData=[[NSMutableArray alloc]init];
    [self addMyObjectIntoDatabase];
    [self initializeTableData];
    self.title=@"Database test";
}

显示内容

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
    NSLog(@"before displaying data");
    cell.textLabel.text=[tableData objectAtIndex:indexPath.row];
    NSLog(@"after displaying data");
    // Configure the cell.
    return cell;
}

这样可以正常显示表的内容。但是现在我想在我的表中插入另一行并显示插入的内容以及之前的内容。由于我是iPhone新手，因此我从教程中学习了读取数据库并显示其内容。如何进一步完成插入和显示的任务？

This is working fine to display the content of table. But now I want to insert another row into my table and display the inserted content along with previous content. Since I am new to iPhone I learnt from tutorials to read the database and display its contents. How do I proceed further to my task of inserting and displaying again?

推荐答案

如果你真的有兴趣学习如何使用SQLite用于管理iPhone应用程序中的数据，我建议您完成以下教程，因为它是一个非常好的介绍：

If you're really interested in learning how to use SQLite to manage data in an iPhone app, I would recommend you to complete the following tutorial, as it's a very good introduction:

iphone-programming-tutorial-creating-a- todo-list-using-sqlite-part-1

本教程使用SQLite处理在iPhone应用程序中选择，更新，插入和删除数据。

The tutorial handles Selecting, Updating, Inserting and Deleting data in an iPhone app, using SQLite.

这篇关于如何将数据插入iPhone中的SQLite数据库的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！