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                  ****ios中FMDB第三方数据库实现增删查改****

一、SQLite (http://www.sqlite.org/docs.html) 是一个轻量级的关系数据库。iOS SDK很早就支持了SQLite，在使用时，只需要加入 libsqlite3.dylib 依赖以及引入 sqlite3.h 头文件即可。但是，原生的SQLite API在使用上相当不友好，在使用时，非常不便。于是，开源社区中就出现了一系列将SQLite API进行封装的库，而FMDB (https://github.com/ccgus/fmdb) 则是开源社区中的优秀者。
FMDB是iOS平台的SQLite数据库框架，是以OC的方式封装了SQLite的C语言API。
二、FMDB由三个主要的类
1）FMDatabase
一个FMDatabase对象就代表一个单独的SQLite数据库
用来执行SQL语句
（2）FMResultSet
使用FMDatabase执行查询后的结果集
（3）FMDatabaseQueue
用于在多线程中执行多个查询或更新，它是线程安全的
三、增删改查
1、创建表
//创建一个名为User的表，有两个字段分别为string类型的Name，integer类型的 Age
[db executeUpdate:@”CREATE TABLE User (Name text,Age integer)”];
2、插入数据
//插入数据使用OC中的类型 text对应为NSString integer对应为NSNumber的整形
[db executeUpdate:@”INSERT INTO User (Name,Age) VALUES (?,?)”,@”张三”,[NSNumber numberWithInt:20]];
3、更新数据
//更新数据 将“张三”更改为“李四”
[db executeUpdate:@”UPDATE User SET Name = ? WHERE Name = ? “,@”李四”,@”张三”];
4、删除数据
//删除数据
[db executeUpdate:@”DELETE FROM User WHERE Name = ?”,@”张三”];
5、查询数据
//返回数据库中第一条满足条件的结果
NSString *aa=[db stringForQuery:@”SELECT Name FROM User WHERE Age = ?”,@”20”];
//返回全部查询结果
FMResultSet rs=[db executeQuery:@”SELECT FROM User”];
rs=[db executeQuery:@”SELECT * FROM User WHERE Age = ?”,@”20”];
while ([rs next]){
NSLog(@”%@ %@”,[rs stringForColumn:@”Name”],[rs stringForColumn:@”Age”]);
}
[rs close];

三、具体代码实现。
1、插入数据
-(void)insertSqlData:(NSString )myname andage:(NSString )myage
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentPath = [paths objectAtIndex:0];
NSString *dbPath = [documentPath stringByAppendingPathComponent:@”goodsdata.db”];

FMDatabase *database = [FMDatabase databaseWithPath:dbPath];
if (![database open]) {
    return;
}else
{
    NSLog(@"打开数据库成功");
}
BOOL insertData = [database executeUpdate:@"insert into goods (name,age)values(?,?)”myname,myage];
if (upDate == NO)
{
    NSLog(@"数据库更新失败。。。。");
}else
{
    NSLog(@"数据更新成功");
}
[database close];

}

2、修改数据
-(void)UpDateSqlData:(NSString )thePiPeiId andAllNumber:(NSString )theAllNumber andAllPrice:(NSString *)theAllPrice
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentPath = [paths objectAtIndex:0];
NSString *dbPath = [documentPath stringByAppendingPathComponent:@”goodsdata.db”];

FMDatabase *database = [FMDatabase databaseWithPath:dbPath];
if (![database open]) {
    return;
}else
{
    NSLog(@"打开数据库成功");
}

//UPDATE 表名称 SET 字段 = 新值 WHERE 主键 = 值  更新语句
BOOL upDate = [database executeUpdate:@"update goods set maxsum=?,AllPrice=? where idstr=?",theAllNumber,theAllPrice,thePiPeiId];
if (upDate == NO)
{
    NSLog(@"数据库更新失败。。。。");
}else
{
    NSLog(@"数据更新成功");
}
[database close];

}
3、查询数据
//查询数据库的内容
- (void)query {
NSLog(@”实现查询”);
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentPath = [paths objectAtIndex:0];
NSString *dbPath = [documentPath stringByAppendingPathComponent:@”goodsdata.db”];

FMDatabase *database = [FMDatabase databaseWithPath:dbPath];
if (![database open]) {

    return;
}

//不需要像Android中那样关闭Cursor关闭FMResultSet，因为相关的数据库关闭时，FMResultSet也会被自动关闭
FMResultSet *resultSet = [database executeQuery:@"select * from goods"];
   while ([resultSet next])
{
     NSLog(@" yes  [resultSet next]");
    NSString *gender = [resultSet stringForColumn:@"goodsid"];
    [dataArray addObject:gender];
    NSString *name = [resultSet stringForColumn:@"goodsname"];
    [nameArray addObject:name];
    NSString *id1 = [resultSet stringForColumn:@"idstr"];
    [IDArray addObject:id1];
    NSString *price = [resultSet stringForColumn:@"pricestr"];
    [priceArray addObject:price];
    NSString * imgUrl = [resultSet stringForColumn:@"imageUrl"];
    [imgArray addObject:imgUrl];


    NSString * GoogsTypeid = [resultSet stringForColumn:@"markprice"];
    NSString * maxNum = [resultSet stringForColumn:@"maxsum"];
    NSString * AllpriceSql = [resultSet stringForColumn:@"AllPrice"];
    NSString * StockSql = [resultSet stringForColumn:@"Stock"];//库存

    //从数据库里面取出数据
    SQlBase = [[BaseProct alloc]initGoodsIdstr:gender andGoodsName:name andIdStr:id1 andMarketPrice:GoogsTypeid andMaxSum:maxNum andPrice:price andProductIdStr:StockSql andProperty1:AllpriceSql andProperty2:imgUrl andstock:nil];
    [SqlBaseArr addObject:SQlBase];
}    
[database close];
//这里也不需要release

}

4、删除数据
-(BOOL)DeteSqlData:(NSString *)thePipeiId
{
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentPath = [paths objectAtIndex:0];
NSString *dbPath = [documentPath stringByAppendingPathComponent:@”goodsdata.db”];

FMDatabase *database = [FMDatabase databaseWithPath:dbPath];
if (![database open]) {
    return NO;
}else
{
    NSLog(@"打开数据库成功");
}
BOOL delete = [database executeUpdate:@"delete from goods where idstr = ?",thePipeiId];
[database close];
return delete;

}

demo下载链接：http://download.csdn.net/detail/eduora_meimei/8472037