sqlite运用总结

1、打开数据库。

//打开数据库
-(BOOL)openDatabase{
	NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
	NSString *paths = [[path objectAtIndex:0] stringByAppendingPathComponent:@"NineCellDiaryDB.sqlite3"];
	if(sqlite3_open([paths UTF8String], &database) != SQLITE_OK){
		[self closeDatabase];
		return NO;
	}return YES;
}

2、关闭数据库。

//关闭数据库
-(BOOL)closeDatabase{
	return (sqlite3_close(database) == SQLITE_OK)?YES:NO;
}

3、插入数据。

//打开数据库
	if(![self openDatabase]){
		[self closeDatabase];
		return NO;
	}
	
	sqlite3_stmt *insert_statement;
	//准备sql语句
	const char* sql = "insert into userinfo(uname,upassword,uexp,uportrait) values(?,?,?,?)";
	//绑定语句值
	if (sqlite3_prepare_v2(database,sql, -1, &insert_statement, NULL) != SQLITE_OK)return NO;
	sqlite3_bind_text(insert_statement, 1, [name UTF8String], -1, SQLITE_TRANSIENT);
	sqlite3_bind_text(insert_statement, 2, [passwd UTF8String], -1, SQLITE_TRANSIENT);
	sqlite3_bind_int(insert_statement, 3, [e intValue]);
	
	//提供png格式和jpg格式支持
	int returnValue = -1;
	NSData *imageData = nil;
        UIImage *por = [UIImage imageNamed:@"kill.png"];
	imageData = UIImagePNGRepresentation(por);//png格式
	if (nil == por) {
		returnValue = sqlite3_bind_blob(insert_statement, 4, nil, -1, NULL);
	}else {
		returnValue = sqlite3_bind_blob(insert_statement, 4,[imageData bytes],[imageData length], NULL);
	}

	//执行插入
	if (sqlite3_step(insert_statement) != SQLITE_DONE) {
		sqlite3_finalize(insert_statement);
		[self closeDatabase];
		return NO;
	}
	sqlite3_finalize(insert_statement);
	[self closeDatabase];

4、更新数据。

//打开数据库
	if(![self openDatabase]){
		[self closeDatabase];
		return NO;
	}
	
	//准备陈述命令
	sqlite3_stmt *update_statement;
	//准备sql语句
	const char* sql = "update userinfo set uname=?,upassword=?,uexp=?,uportrait=? where id=1";
	//绑定语句值
	if (sqlite3_prepare_v2(database,sql, -1, &update_statement, NULL) != SQLITE_OK)return NO;
	sqlite3_bind_text(update_statement, 1, [name UTF8String], -1, SQLITE_TRANSIENT);
	sqlite3_bind_text(update_statement, 2, [passwd UTF8String], -1, SQLITE_TRANSIENT);
	sqlite3_bind_int(update_statement, 3, [e intValue]);
	
	//提供png格式和jpg格式支持
	int returnValue = -1;
	NSData *imageData = nil;
	UIImage *por = [UIImage imageNamed:@"killer.png"];
	if (nil == por) {
		returnValue = sqlite3_bind_blob(update_statement, 4, nil, -1, NULL);  
        }else {
		imageData = UIImageJPEGRepresentation(por,1.0f);//jpg格式
		returnValue = sqlite3_bind_blob(update_statement, 4,[imageData bytes],[imageData length], NULL);
		}
	}

	//执行
	if (sqlite3_step(update_statement) != SQLITE_OK){
		sqlite3_finalize(update_statement);
		[self closeDatabase];
		return NO;
	}
	sqlite3_finalize(update_statement);
	[self closeDatabase];

5、查询数据

//打开数据库
		if (![self openDatabase]) {
			return self;
		}
		
		//查询所有数据
		sqlite3_stmt *statement;
		const char* zTail;
		sqlite3_prepare_v2(database,"SELECT * from userinfo;",-1,&statement,&zTail); 
		
        const unsigned char *name; 
		const unsigned char *password;
		int exp=0;
		NSString *newName = nil;
		NSString *newPassword = nil;
		NSData *imgData = nil;

		[color=green]//sqlite3_reset(statement);[/color]

		if (SQLITE_ROW == sqlite3_step(statement)) {
			name = sqlite3_column_text(statement,1);
			password = sqlite3_column_text(statement,2);
			exp = sqlite3_column_int(statement,3);
			if (NULL != sqlite3_column_blob(statement,4)) {
				imgData = [[NSData alloc] initWithBytes:sqlite3_column_blob(statement,4) length:sqlite3_column_bytes(statement, 1)];
			}
			newName = [NSString stringWithCString:name encoding:CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingUTF8)];
			newPassword = [NSString stringWithCString:password encoding:CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingUTF8)];
		}