FMDB基本操作

1.实例化FMDatabase
//paths： ios下Document路径，Document为ios中可读写的文件夹
NSArray *paths =NSSearchPathForDirectori<wbr>esInDomains(NSDocumentDirectory,NSUserDomainMask, YES);<br> NSString *documentDirectory = [paths objectAtIndex:0];</wbr>

//dbPath： 数据库路径，在Document中。
NSString *dbPath = [documentDirectorystringByAppendingPathCom<wbr>ponent:@"Test.db"];</wbr>

//创建数据库实例 db<wbr>这里说明下:如果路径中不存在"Test.db"的文件,sqlite会自动创建"Test.db"<br> FMDatabase *db= [FMDatabase databaseWithPath:dbPath] ;<br> if (![db open]) {<br> NSLog(@"Could not open db.");<br> return ;<br> }</wbr>

2.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,Ageinteger)"];

3.插入
//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]];

4.更新
//更新数据 将“张三”更改为“李四”
[db executeUpdate:@"UPDATE User SET Name = ? WHERE Name = ?",@"李四",@"张三"];

5.删除
//删除数据
[db executeUpdate:@"DELETE FROM User WHERE Name = ?",@"张三"];

6.查询
//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"],[rsstringForColumn:@"Age"]);
}

[rs close];