FMDB操作数据库

#define KDataBasePath @“...”
FMDatabase *db = [FMDatabase databaseWithPath:KDataBasePath];```
1、打开数据库
[db open]
2、creat insert 用同一方法：将SQL语句转化为NSString 
[db executeUpdate:SQLCommandString]；

3、select 查询用query 返回值：FMResultSet类型 是个集合
FMResultSet *result = [db executeQuery:SQLCommandString]；
if ([result next]) {
   NSLog(@"select success");
   //拿出查询的字段数据
   [result stringForColumn:@"name"];
}
4、关闭数据库
[db close];

例子：

打开数据库
#define KDataBasePath @“...”
FMDatabase *db = [FMDatabase databaseWithPath:KDataBasePath];
    if (![db open]) {
        NSLog(@"could not open db");
        return;
    }else {
        NSLog(@"open db");
    }```

创建数据表 
-(void)creatTableWithTableName
{
    NSString *creatString = [NSString stringWithFormat:@"CREATE TABLE IF NOT EXISTS 'user' ('id' INTEGER PRIMARY KEY AUTOINCREMENT, 'name' TEXT,  'password' TEXT)"];

    BOOL result = [db executeUpdate:creatString];
    if (result) {
        NSLog(@"tabel success");
    }else {
        NSLog(@"tabel fail");
    }
}

查询数据表是否存在
-(void)queryTable:(NSString *)tableName
{

    if ([db executeQuery:@"select count(*) as 'count' from sqlite_master where type = 'table' and name = %@",tableName]) {
        NSLog(@"tabel 已存在");
    }else {
        NSLog(@"tabel 不存在");
    }
}

插入一条数据
-(BOOL)insertDataWithId:(NSInteger)user_id
                   Name:(NSString *)name
               Password:(NSString *)password

{
    //有问题------
   BOOL result = [db executeUpdate:@"insert into user (name,password) values (?,?)",name,password];
    if (result) {
        NSLog(@"insert success");
    }else {
        NSLog(@"insert fail");
    }
    return result;
}

select选择数据
-(BOOL)selectTableWithUserName:(NSString *)name Password:(NSString *)password
{
    BOOL resultSelect = NO;
    NSString *selectString = [NSString stringWithFormat:@"select *from 'user' where name = '%@' and password = '%@'",name,password];
    FMResultSet *result = [db executeQuery:selectString];
    if ([result next]) {
        resultSelect = YES;

        NSLog(@"select success");
        NSLog(@"%@",[result stringForColumn:@"name"]);
    }else{
        NSLog(@"select fail");
    }
    return resultSelect;
}

关闭数据库
-(void)closeDataBase
{
    if (![db close]) {
        NSLog(@"数据库关闭异常，请检查");
        return;
    }else {
        NSLog(@"关闭成功");
    }
}