把數據庫文件從工程中移動到本地

最近有這麼一個需求,數據庫初始的時候就已經有一個表中有數據了,這致使咱們以前在程序運行的時候,再在本地建立數據庫的方案不能使用了.由於程序運行時,再建立數據庫和表,確定都是空的.若是要有數據,就必須寫n多條的插入語句.最終,咱們以爲把已經建立好的數據庫,放到工程文件,Supporting Files 中.而後在程序運行的時候,把數據庫移動到本地,做爲本地數據庫使用.

//  SQLManager.h

#import <Foundation/Foundation.h>

@interface  SQLManager : NSObject

+ (instancetype)sharedMapSQLite;

- (NSArray *)totalGroupOfT_cityWithNameSort:(NSString *)nameSort;

@end

//  SQLManager.m

#import "SQLManager.h"

#import "FMDB.h"

@interface SQLManager ()

@property (nonatomic, strong) FMDatabaseQueue* queue;

@end

@implementation SQLManager

+ (instancetype)sharedSQLManager {

    static SQLManager* manager;

    static dispatch_once_t onceToken;

    dispatch_once(&onceToken, ^{

        manager = [[MapSQLite alloc] init];

        NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];

        path = [path stringByAppendingPathComponent:@"list.db"];

        NSData *data=[NSData dataWithContentsOfFile:path];

        

        if (!data) {

            NSString *backupDbPath = [[NSBundle mainBundle]

                                      pathForResource:@"list"

                                      ofType:@"db"];

            NSFileManager *fm = [NSFileManager defaultManager];

            

            NSError *error;

            BOOL cp = [fm copyItemAtPath:backupDbPath toPath:path error:&error];

            NSLog(@"%@",error);

        }

        

        manager.queue = [FMDatabaseQueue databaseQueueWithPath:path];

        NSLog(@"path == %@",path);

    });

     return manager;

}

//根據傳入的字母主鍵 返回主鍵所在色數組

- (NSArray *)totalGroupOfT_cityWithNameSort:(NSString *)nameSort

{

    NSString* loadStatement = @"SELECT * FROM T_city WHERE  nameSort = ?;";

    NSMutableArray *arrayM = [NSMutableArray array];

    [self.queue inTransaction:^(FMDatabase *db, BOOL *rollback) {

        FMResultSet* result = [db executeQuery:loadStatement withArgumentsInArray:@[nameSort]];

        while ([result next]) {

            NSString *strgroup = [result stringForColumn:@"CityName"];

            [arrayM addObject:strgroup]; 

        }

    }];

    return arrayM.copy;

    

}

// 調用

    SQLManager *manager = [SQLManager sharedMapSQLite];

    NSArray *array = [manager totalGroupOfT_cityWithNameSort:@"A"];

    NSLog(@"%@",array);