FMDB介绍:
FMDB是iOS平台的SQLite的数据库框架,(用oc封装的)。
其中主要有三核心类:
1.FMDatabase
一个FMDatabase对象代表一个单独的SQLite数据库
2.FMResultSet
使用FMDatabase执行查询后得结果集
3.FMDatabaseQueue
用于在多线程中执行多个查询或更新,线程安全的
执行更新
在FMDB中,除查询以外的所有操作,都称之为更新。
使用executeUpdate:
-(BOOL)executeUpdate:(NSString *)sql,...
-(BOOL)executeUpdateWithFormat:(NSString *)format,...
-(BOOL)executeUpdate:(NSString *)sql withArgumentsInArray:(NSArray *)arguments
示例
[db executeUpdate:@"UPDATE student set age = ? where name = ?;" @20,@"JAck"];
查询方法
-(FMResultSet *)executeQuery:(NSString *)sql,..
-(FMResultSet *)executeQueryWithFormat:(NSString *)format,..
-(FMResultSet *)executeQuery:(NSString *)sql withArgumentsInArray:(NSArray *)arguments
示例
FMResultSet *rs = [db executeQuery:@"select * from student"];
遍历结果集
while([rs next]){
NSString *name = [rs stringForColumn:@"name"];
int age = [rs intForColumn:@"age"];
double score = [rs doubleForColumn:@"score"];
}
使用FMDB
在https://github.com网站,下载FMDB的第三方类库。
1新建工程,倒入
2.将FMDB的三方库添加进去
定义数据库:
#import "ViewController.h"
#import "FMDB.h"
@interface ViewController ()
@property (nonatomic,strong) FMDatabase *db;
@end
获取沙盒文件路径,有文件获取,无文件创建
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSString *doc = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString *fileName = [doc stringByAppendingPathComponent:@"PersonDatabase.sql"];
FMDatabase *db = [FMDatabase databaseWithPath:fileName];
if([db open]){
BOOL result = [db executeUpdate:@"CREATE TABLE IF NOT EXISTS student (id integer PRIMARY KEY AUTOINCREMENT, name text NOT NULL, age integer NOT NULL);"];
if (result) {
NSLog(@"创表成功");
}else{
NSLog(@"创表失败");
}
}
self.db = db;
}
执行插入操作:
-(void)insert{
for (int i = 0; i < 10; i++) {
NSString *name = [NSString stringWithFormat:@"jack-%d",arc4random_uniform(100)];
[self.db executeUpdate:@"INSERT INTO student(name,age) VALUES (?,?);",name,@(arc4random_uniform(40))];
}
}
查询操作:
-(void)query{
// 1.执行查询语句
FMResultSet *resultSet = [self.db executeQuery:@"SELECT * FROM student"];
// 2.遍历结果
while ([resultSet next]) {
int ID = [resultSet intForColumn:@"id"];
NSString *name = [resultSet stringForColumn:@"name"];
int age = [resultSet intForColumn:@"age"];
NSLog(@"id = %d, name = %@, age = %d", ID, name, age);
}
}
删除操作:
-(void)delete{
[self.db executeUpdate:@"DROP TABLE IF EXISTS student;"];
[self.db executeUpdate:@"CREATE TABLE IF NOT EXISTS student (id integer PRIMARY KEY AUTOINCREMENT, name text NOT NULL, age integer NOT NULL);"];
}