IOS 开发学习33 使用sqlite3

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sqlite3 命令行简单使用

sqlite3 路径 //打开数据库路径连接
select * from sqlite_master where type=”table”; //显示所有表结构
select * from testable; //显示某张表数据
.tables //查看表
.help //查看帮助
.quit //退出

xcode使用sqlite3步骤

1.添加libsqlite3.dylib

这里写图片描述

2.头文件

////  DbUtils.h//  smart////  Created by 谢厂节 on 15/5/12.//  Copyright (c) 2015年 WHR. All rights reserved.//#import <Foundation/Foundation.h>#import "sqlite3.h"@interface DbUtils : NSObject{    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里边操作-(void)openDB;-(void)closeDB;-(NSMutableArray *)getAllTypes;@end

.m文件

////  DbUtils.m//  smart////  Created by 谢厂节 on 15/5/12.//  Copyright (c) 2015年 WHR. All rights reserved.//#import "DbUtils.h"#import "KMTypes.h"#import "KMContents.h"@implementation DbUtils//打开数据库的方法- (void)openDB{       ///文件是否存在    NSFileManager* fileManager = [NSFileManager defaultManager];    NSString *dbpath=[self filePath];    NSLog(@"database path:%@",dbpath);    BOOL success = [fileManager fileExistsAtPath:dbpath];    if (!success) {        NSString *resourcePath=[[NSBundle mainBundle]resourcePath];        //自动复制        NSString *sourceDBPath=[resourcePath stringByAppendingPathComponent:@"app.bundle/datas.sqlite"];        NSError *error;        success = [fileManager copyItemAtPath:sourceDBPath toPath:dbpath error:&error];        if(!success)            NSAssert1(0,@"数据库附加失败！'%@'.", [error localizedDescription]);        else            NSLog(@"数据库附加成功:%@",dbpath);    }    if (sqlite3_open([[self filePath] UTF8String], &db) != SQLITE_OK) {        sqlite3_close(db);        NSAssert(0, @"数据库打开失败。");    }}- (void)closeDB{    sqlite3_close(db);}//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:@"datas.sqlite"];}////查询数据所有类别- (NSMutableArray *)getAllTypes{    [self openDB];    NSMutableArray *array=[NSMutableArray arrayWithCapacity:6 ];    NSString *sql = @"SELECT * FROM km_types";    sqlite3_stmt *statement;    if (sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil) == SQLITE_OK) {        while (sqlite3_step(statement) == SQLITE_ROW) {            KMTypes* k= [[KMTypes alloc]init];            int type_id = (int)sqlite3_column_int(statement,0);            int parent_id = (int)sqlite3_column_int(statement,1);            char *type_title = (char *)sqlite3_column_text(statement, 2);            int type_order = (int)sqlite3_column_int(statement,3);            int topic_count=(int)sqlite3_column_int(statement,4);            NSString *type_titleStr = [[NSString alloc] initWithUTF8String:type_title];            k.type_title = type_titleStr;            k.type_id=type_id;            k.parent_id = parent_id;            k.type_order = type_order;            k.topic_count=topic_count;            [array addObject:k];        }        sqlite3_finalize(statement);    }    [self closeDB];    return array;}@end这里只实现一个简单的查询功能。

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