sqlite的应用实例

标签：sqlite3   模型   数据库连接   数据库中获取数据   数据库   

声明：下面的代码是引用别人的：

代码截图：

  运行的结果图：

下面是程序中主要的代码：

模型product的代码：

product.h 的文件爱你
#import <Foundation/Foundation.h>

//这个就是模型类，对应这数据库中的属性字段。
@interface Product : NSObject {
    int ID;
    NSString* name;
    NSString* manufacturer;
    NSString* details;
    float price;
    int quantity;
    NSString* countryOfOrigin;
    NSString* image;
}

@property (nonatomic) int ID;
@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) NSString *manufacturer;
@property (strong, nonatomic) NSString *details;
@property (nonatomic) float price;
@property (nonatomic) int quantity;
@property (strong, nonatomic) NSString *countryOfOrigin;
@property (strong, nonatomic) NSString *image;

@end

product.m文件，尤其这样实现是为了和在字段中的属性名字对应。
#import "Product.h"

@implementation Product

@synthesize ID;
@synthesize name;
@synthesize manufacturer;
@synthesize details;
@synthesize price;
@synthesize quantity;
@synthesize countryOfOrigin;
@synthesize image;

@end

下面是DBAccess类的代码：

DBAccess.h文件。
#import <Foundation/Foundation.h>

// This includes the header for the SQLite library.
#import <sqlite3.h>
#import "Product.h"

//用来获取数据库中的数据，添加到模型中库

@interface DBAccess : NSObject {
    
    
}

//获取的数组方法
- (NSMutableArray*) getAllProducts;
//关闭数据库
- (void) closeDatabase;

//初始化数据库，包括打开数据库
- (void)initializeDatabase;

@end

DBAccess.m文件。
#import "DBAccess.h"

@implementation DBAccess

// Reference to the SQLite database.
sqlite3* database;

//初始化方法，集成NSObject类，启动的时候就会调用这个方法。
-(id) init
{
    if ((self = [super init]))
    {
        [self initializeDatabase];
    }
    return self;
}

// 获取数据库文件、打开、连接
- (void)initializeDatabase {
    
    // Get the database from the application bundle.
    NSString *path = [[NSBundle mainBundle]
                      pathForResource:@"catalog"
                      ofType:@"db"];
    
    // Open the database.
    if (sqlite3_open([path UTF8String], &database) == SQLITE_OK)
    {
        NSLog(@"Opening Database");
    }
    else
    {
        // Call close to properly clean up
        sqlite3_close(database);
        NSAssert1(0, @"Failed to open database: ‘%s’.",
                  sqlite3_errmsg(database));
    }
}

//关闭数据库
-(void) closeDatabase
{
    // Close the database.
    if (sqlite3_close(database) != SQLITE_OK) {
        NSAssert1(0, @"Error: failed to close database: ‘%s’.",
                  sqlite3_errmsg(database));
    }
}

//获取数据库中product的所有记录存储到数组中
- (NSMutableArray*) getAllProducts
{
    NSLog(@"获取数据");
    //  The array of products that we will create
    NSMutableArray *products = [[NSMutableArray alloc] init];

    //  The SQL statement that we plan on executing against the database
    const char *sql = "SELECT product.ID,product.Name,     Manufacturer.name,product.details,product.price,    product.quantityonhand, country.country,     product.image FROM Product,Manufacturer,     Country where manufacturer.manufacturerid=product.manufacturerid     and product.countryoforiginid=country.countryid";

    //  The SQLite statement object that will hold our result set
    sqlite3_stmt *statement;
    
    // Prepare the statement to compile the SQL query into byte-code
    int sqlResult = sqlite3_prepare_v2(database, sql, -1, &statement, NULL);

    if ( sqlResult== SQLITE_OK) {
        // Step through the results - once for each row.
        //#define SQLITE_ROW   sqlite3_step() has another row ready
        while (sqlite3_step(statement) == SQLITE_ROW) {
            //  allocate a Product object to add to products array
            Product  *product = [[Product alloc] init];
            // The second parameter is the column index (0 based) in
            // the result set.
            char *name = (char *)sqlite3_column_text(statement, 1);
            char *manufacturer = (char *)sqlite3_column_text(statement, 2);
            char *details = (char *)sqlite3_column_text(statement, 3);
            char *countryOfOrigin = (char *)sqlite3_column_text(statement, 6);
            char *image = (char *)sqlite3_column_text(statement, 7);
            
            //  Set all the attributes of the product
            product.ID = sqlite3_column_int(statement, 0);
            product.name = (name) ? [NSString stringWithUTF8String:name] : @"";
            product.manufacturer = (manufacturer) ? [NSString
                                                     stringWithUTF8String:manufacturer] : @"";
            product.details = (details) ? [NSString stringWithUTF8String:details] : @"";
            product.price = sqlite3_column_double(statement, 4);
            product.quantity = sqlite3_column_int(statement, 5);
            product.countryOfOrigin = (countryOfOrigin) ? [NSString
                                                           stringWithUTF8String:countryOfOrigin] : @"";
            product.image = (image) ? [NSString stringWithUTF8String:image] : @"";
            
            // 将产品添加到Products数组中并且移到下一行
            [products addObject:product];
        }
        //释放和编译器语句有关的资源
        sqlite3_finalize(statement);
    }
    else {
        NSLog(@"Problem with the database:");
        NSLog(@"%d",sqlResult);
    }
    return products;
}
@end





 

在Controller中使用来显示在View中的代码：

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    DBAccess *dbAccess = [[DBAccess alloc] init];
    
    self.products = [dbAccess getAllProducts]; //前面应该定义了products这个属性。
    
    [dbAccess closeDatabase];
    
}

源代码下载连接：

http://www.wrox.com/WileyCDA/WroxTitle/Professional-iOS-Database-Application-Programming-2nd-Edition.productCd-1118391845,descCd-DOWNLOAD.html

sqlite的应用实例

标签：sqlite3   模型   数据库连接   数据库中获取数据   数据库   

原文地址：http://blog.csdn.net/u012496940/article/details/47809311