可以进行数据库建表，以及增删改査等操作

使用前需要导入sqlite3数据库包

SandBoxPath.h

#import <Foundation/Foundation.h>

@interface SandBoxPath : NSObject

//沙盒的主路径
+ (NSString *)homePath;
//沙盒中Documents路径
+ (NSString *)documents;
//沙盒中libraray路径
+ (NSString *)library;
//libraryCaches路径
+ (NSString *)libraryCaches;
//temp路径
+ (NSString *)temp;

@end

SandBoxPath.m

#import "SandBoxPath.h"

@implementation SandBoxPath

//得到沙盒主目录
+ (NSString *)homePath
{
    return  NSHomeDirectory();
}

//得到Documents文件夹目录
+ (NSString *)documents
{
    return NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES).firstObject;
}

//得到Library文件夹目录
+ (NSString *)library
{
    return NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES).firstObject;
}

//得到caches文件夹
+ (NSString *)libraryCaches
{
    return NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES).firstObject;
}

//得到tem文件夹
+ (NSString *)temp
{
    return NSTemporaryDirectory();
}
@end

DataBaseHelper.h

#import <Foundation/Foundation.h>
#import <sqlite3.h>

@interface DataBaseHelper : NSObject

+ (instancetype)sharedDatabaseHelper;

//创建数据库文件路径
- (void)dbFilePathWithFileName: (NSString *)fileName;

//除了查询语句以外的所有语句
- (void)operationSQLWithSqlString: (NSString *)sqlstr;

//查询语句
- (NSArray *)queryDataWithSqlstring: (NSString *)sqlString;
@end

DataBaseHelper.m

#import "DataBaseHelper.h"
#import "SandBoxPath.h"

@interface DataBaseHelper ()

@property (nonatomic,retain) NSString *fileName;

@end

@implementation DataBaseHelper

+ (instancetype)sharedDatabaseHelper
{
    static DataBaseHelper *dataBaseHelper = nil;
    @synchronized(self) {
        if (!dataBaseHelper) {
            dataBaseHelper = [[DataBaseHelper alloc] init];
        }
        
        return dataBaseHelper;
    }  
}

//创建数据库文件路径
- (void)dbFilePathWithFileName: (NSString *)fileName
{
    //得到沙盒的documents路径
    NSString *docuPath = [SandBoxPath documents];
    //判断文件名是否带后缀，如果有直接使用，如果没有，内部为它拼接
    if (![fileName containsString:@".sqlite"])
    {
        fileName = [fileName stringByAppendingString:@".sqlite"];
    }
    
    self.fileName = [docuPath
                     stringByAppendingPathComponent:fileName];
}

//打开或者创建数据库
- (sqlite3 *)openOrCreateDB
{
    sqlite3 *sqlDB = NULL;
    //打开数据库
    int result = sqlite3_open(self.fileName.UTF8String, &sqlDB);
    if (result == SQLITE_OK) {
        NSLog(@"数据库打开成功");
        return sqlDB;
    }
    else
    {
        NSLog(@"数据库打开失败");
        return NULL;
    }
}

//除了查询操作，其他操作所执行的方法
- (void)operationSQLWithSqlString: (NSString *)sqlstr
{
    sqlite3 *sqlDB = [self openOrCreateDB];
    int result = sqlite3_exec(sqlDB, sqlstr.UTF8String, NULL, NULL, NULL);
    if (result == SQLITE_OK) {
        
        NSLog(@"语句执行成功");
        //每次执行完成之后，需要关闭数据库
        sqlite3_close(sqlDB);
        NSLog(@"%@",self.fileName);
    }
    else
    {
        NSLog(@"语句执行失败");
        //每次执行完成之后，需要关闭数据库
        sqlite3_close(sqlDB);
    }
}

//数据库查询，通用
- (NSArray *)queryDataWithSqlstring: (NSString *)sqlString
{
    //初始化可变数据，用来盛放所有记录
    NSMutableArray *resultArray = [[NSMutableArray alloc] init];
    //打开数据库
    sqlite3 *sqlDB = [self openOrCreateDB];
    //声明stmt指针，一会用来盛放
    sqlite3_stmt *stament = NULL;
    int result = sqlite3_prepare(sqlDB, sqlString.UTF8String, -1, &stament, NULL);
    if (result == SQLITE_OK) {
        //没执行一次step函数，stament中就会完整的保存一条记录
        while (sqlite3_step(stament) == SQLITE_ROW) {
            //确定该表有几个字段，其实就是有几列
            int columnCount = sqlite3_column_count(stament);
            
            NSMutableDictionary *mDict = [NSMutableDictionary dictionary];
            //遍历所有的列
            for (int i = 0; i < columnCount; i++) {
                int type = sqlite3_column_type(stament, i);
                //得到字段名称
                const char *attName = sqlite3_column_name(stament, i);
                NSString *keyString = [NSString stringWithCString:attName encoding:NSUTF8StringEncoding];
                switch (type) {
                    case SQLITE_INTEGER:
                        {
                            int value = sqlite3_column_int(stament,i);
                            [mDict setObject:[NSNumber numberWithInt:value] forKey:keyString];
                        }
                        break;
                    case SQLITE_TEXT:
                        {
                            NSString *valueString = [NSString stringWithCString:(const char *)sqlite3_column_text(stament, i) encoding:NSUTF8StringEncoding];
                            [mDict setObject:valueString forKey:keyString];
                        }
                        break;
                    case SQLITE_FLOAT:
                        {
                            float value = sqlite3_column_int(stament,i);
                            [mDict setObject:[NSNumber numberWithFloat:value] forKey:keyString];
                        }
                        break;
                    default:
                        break;
                }
            }
            [resultArray addObject:mDict];
        }
    }
    
    sqlite3_close(sqlDB);
    sqlite3_finalize(stament);
    
    return resultArray;
}
@end