ios 怎样打开sqlite数据库

新建Empty Appliation，添加一个HomeViewController，和一个组件libsqlite3.dylib,来支持对sqlite3的连接，关闭，增删改查等 *** 作。

1. HomeViewController.h代码：

#import <UIKit/UIKit.h>

#import "sqlite3.h"

@interface HomeViewController : UIViewController{

sqlite3 *db//声明一个sqlite3数据库

}

- (NSString *)filePath//数据库文件的路径。一般在沙箱的Documents里边 *** 作

@end

2. HomeViewController.m代码：

#import "HomeViewController.h"

@interface HomeViewController ()

@end

@implementation HomeViewController

//该方法用于返回数据库在Documents文件夹中的全路径信息

- (NSString *)filePath{

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)

NSString *documentsDir = [paths objectAtIndex:0]

return [documentsDir stringByAppendingPathComponent:@"Contacts.sqlite"]

}

//打开数据库的方法

- (void)openDB{

if (sqlite3_open([[self filePath] UTF8String], &db) != SQLITE_OK) {

sqlite3_close(db)

NSAssert(0, @"数据库打开失败。")

}

}

- (void)getAllContacts{

NSString *sql = @"SELECT * FROM members"

sqlite3_stmt *statement

if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil) == SQLITE_OK) {

while (sqlite3_step(statement) == SQLITE_ROW) {

char *name = (char *)sqlite3_column_text(statement, 0)

NSString *nameStr = [[NSString alloc] initWithUTF8String:name]

char *email = (char *)sqlite3_column_text(statement, 1)

NSString *emailStr = [[NSString alloc] initWithUTF8String:email]

char *birthday = (char *)sqlite3_column_text(statement, 2)

NSString *birthdayStr = [[NSString alloc] initWithUTF8String:birthday]

NSString *info = [[NSString alloc] initWithFormat:@"%@ - %@ - %@",

nameStr, emailStr, birthdayStr]

NSLog(info)

[nameStr release]

[emailStr release]

[birthdayStr release]

[info release]

}

sqlite3_finalize(statement)

}

}

实际上libsqlite3.0.dylib本身是个链接，它指向libsqlite3.dylib。也就是说在项目里如果你添加libsqlite3.dylib和添加libsqlite3.0.dylib其实是添加了同一个文件，没有区别，那为什么要添加libsqlite3.dylib呢？

其实这个指针总是指向最新的sqlite3动态库，比如说sqlite3库更新了，如果我们引用的是libsqlite3.0.dylib你就不需要做任何修改了。

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