首先要先导入第三方类库FMdatabase
+(NSString *)databaseFilePath
{
NSArray *filePath = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory ,NSUserDomainMask , YES );
NSString *documentPath = [filePath objectAtIndex: 0];
NSLog( @"%@",filePath);
NSString *dbFilePath = [documentPath stringByAppendingPathComponent: @"db.sqlite"];
return dbFilePath;}
创建数据库的操作
+(void)creatDatabase
{
db = [[ FMDatabasedatabaseWithPath :[ selfdatabaseFilePath ]] retain ];
}
创建表
+(void)creatTable
{
//先判断数据库是否存在，如果不存在，创建数据库
if (! db) {
[ selfcreatDatabase ];
}
//判断数据库是否已经打开，如果没有打开，提示失败
if (![ db open]) {
NSLog (@" 数据库打开失败" );
}
return ;
//为数据库设置缓存，提高查询效率
[ dbsetShouldCacheStatements : YES ];
//判断数据库中是否已经存在这个表，如果不存在则创建该表
if (![ dbtableExists : @"people" ])
{
[ db executeUpdate :@"CREATE TABLES people(people_id INTEGER PRIMARY KEY AUTOINCREAMENT,name TEXT,age INTEGER) " ];
}
NSLog (@" 创建完成" );
}
增加表数据
+(void)insertPeople:(People *)aPeople
{
if (! db) {
[ selfcreatDatabase ];
}
if (![ db open]) {
NSLog (@" 数据库打开失败" );
}
return ;
[ dbsetShouldCacheStatements : YES ];
if (![ dbtableExists : @"people" ])
{
[ selfcreatTable ];
}
//以上操作与创建表是做的判断逻辑相同//现在表中查询有没有相同的元素，如果有，做修改操作
FMResultSet *rs = [ db executeQuery :@"select * from people where people_id = ?" ,[ NSString stringWithFormat :@"%d" ,aPeople. peopleID ]];
if([rs next])
{
NSLog (@"dddddslsdkien" );
}
[ db executeUpdate :@"update people set name = ?,age = ? where people_id = 1" ,aPeople. name ,[ NSString stringWithFormat :@"%d" ,aPeople. age ]];
//向数据库中插入一条数据
else {
[ db executeUpdate :@"INSERT INTO people (name,age) VALUES (?,?)" ,aPeople. age ]];
}
}
删除数据
+(void)deletePeopleByID:(int)ID
{
if (! db) {
[ selfcreatDatabase ];
}
if (![ db open]) {
NSLog (@" 数据库打开失败" );
}
return ;
[ dbsetShouldCacheStatements : YES ];
//判断表中是否有指定的数据， 如果没有则无删除的必要，直接return
if (![ dbtableExists : @"people" ])
{
return ;
}
//删除操作
[ db executeUpdate :@"delete from people where people_id = ?" ,ID]];
[ db close];}
+(NSArray *)getAllPeople
{
if (! db) {
[ selfcreatDatabase ];
}
if (![ db open]) {
NSLog (@" 数据库打开失败" );
}
return nil ;
[ dbsetShouldCacheStatements : YES ];
if (![ dbtableExists : @"people" ])
{
return nil ;
}
//定义一个可变数组，用来存放查询的结果，返回给调用者
NSMutableArray *peopleArray = [[NSMutableArray alloc ] initWithArray : 0 ];//定义一个结果集，存放查询的数据
FMResultSet *rs = [ db executeQuery :@"select * from people" ];//判断结果集中是否有数据，如果有则取出数据
while ([rs next]) {
People *aPeople = [[ People alloc] init];
}
aPeople. peopleID = [rs intForColumn: @"people_id"];
aPeople. name = [rs stringForColumn: @"name"];
aPeople. age = [rs intForColumn: @"age"];
//将查询到的数据放入数组中。
[peopleArray addObject:aPeople];
return [peopleArray autorelease];}