如何在iPhone SDK中将SQLite文件导出为CSV文件 [英] How to export SQLite file into CSV file in iPhone SDK

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本文介绍了如何在iPhone SDK中将SQLite文件导出为CSV文件的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

在我的应用程序,我想导出一个SQLite数据库文件到CSV文件..

In my app, I want to export a SQLite database file to CSV file..

你能建议我如何做到这一点?
谢谢。

Could you suggest me how to do this? Thanks.

推荐答案

首先,您需要确保使用 FMDB 访问数据库,因为在Objective-C中直接使用SQLite C API的人是受虐者。您可以这样做:

First, you'll want to make sure that you're using FMDB to access the database, because people who use the SQLite C API directly in Objective-C are masochists. You can do that like this:

FMDatabase *db = [[FMDatabase alloc] initWithPath:@"/path/to/db/file"];
FMResultSet *results = [db executeQuery:@"SELECT * FROM tableName"];
while([results nextRow]) {
  NSDictionary *resultRow = [results resultDict];
  NSArray *orderedKeys = [[resultRow allKeys] sortedArrayUsingSelector:@selector(compare:)];
  //iterate over the dictionary
}

文件,以及还有代码

#import "CHCSV.h"

CHCSVWriter * csvWriter = [[CHCSVWriter alloc] initWithCSVFile:@"/path/to/csv/file" atomic:NO];

//write stuff
[csvWriter closeFile];
[csvWriter release];

要结合使用,您可以这样做:

And to combine them, you'd do:

FMDatabase *db = [[FMDatabase alloc] initWithPath:@"/path/to/db/file"];
if (![db open]) {
  //couldn't open the database
  [db release];
  return nil;
}
FMResultSet *results = [db executeQuery:@"SELECT * FROM tableName"];
CHCSVWriter *csvWriter = [[CHCSVWriter alloc] initWithCSVFile:@"/path/to/csv/file" atomic:NO];
while([results nextRow]) {
  NSDictionary *resultRow = [results resultDict];
  NSArray *orderedKeys = [[resultRow allKeys] sortedArrayUsingSelector:@selector(compare:)];
  //iterate over the dictionary
  for (NSString *columnName in orderedKeys) {
    id value = [resultRow objectForKey:columnName];
    [csvWriter writeField:value];
  }
  [csvWriter writeLine];
}
[csvWriter closeFile];
[csvWriter release];

[db close];
[db release];

这将写入 tableName 表格转换为CSV文件。

That will write the contents of the tableName table out to a CSV file.

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