IOS开发数据库篇 --- FMDatabaseQueue数据库队列安全操作
#import "FMDB.h"
@interface CZViewController ()
- (IBAction)insertOnClick;
- (IBAction)deleteOnClick;
- (IBAction)updateOnClick;
- (IBAction)queryOnClick;
//@property (nonatomic, strong) FMDatabase *db;
@property (nonatomic, strong) FMDatabaseQueue *queue;
@end
@implementation CZViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// 0.获取沙盒地址
NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject];
NSString *sqlFilePath = [path stringByAppendingPathComponent:@"student.sqlite"];
// 1.创建一个FMDatabaseQueue对象
// 只要创建数据库队列对象, FMDB内部就会自动给我们加载数据库对象
self.queue = [FMDatabaseQueue databaseQueueWithPath:sqlFilePath];
// 2.执行操作
// 会通过block传递队列中创建好的数据库给我们
[self.queue inDatabase:^(FMDatabase *db) {
// 编写需要执行的代码
// 2.1创建表(在FMDB框架中, 增加/删除/修改/创建/销毁都统称为更新)
BOOL success = [db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, score REAL DEFAULT 1);"];
if (success) {
NSLog(@"创建表成功");
}else
{
NSLog(@"创建表失败");
}
}];
/*
// 1.加载数据库对象
self.db = [FMDatabase databaseWithPath:sqlFilePath];
// 2.打开数据库
if([self.db open])
{
NSLog(@"打开成功");
// 2.1创建表(在FMDB框架中, 增加/删除/修改/创建/销毁都统称为更新)
BOOL success = [self.db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, score REAL DEFAULT 1);"];
if (success) {
NSLog(@"创建表成功");
}else
{
NSLog(@"创建表失败");
}
}else
{
NSLog(@"打开失败");
}
*/
}
- (IBAction)insertOnClick
{
/*
// FMDB中可以用?当作占位符, 但是需要注意: 如果使用问号占位符, 以后只能给占位符传递对象
BOOL success = [self.db executeUpdate:@"INSERT INTO t_student(score, name) VALUES (?, ?);", @(20), @"Jack"];
if (success) {
NSLog(@"插入成功");
}else
{
NSLog(@"插入失败");
}
*/
[self.queue inDatabase:^(FMDatabase *db) {
BOOL success = [db executeUpdate:@"INSERT INTO t_student(score, name) VALUES (?, ?);", @(20), @"jackson"];
if (success) {
NSLog(@"插入成功");
}else
{
NSLog(@"插入失败");
}
}];
}
- (IBAction)deleteOnClick
{
}
- (IBAction)updateOnClick
{
/*
[self.queue inDatabase:^(FMDatabase *db) {
// 开启事务
[db beginTransaction];
[db executeUpdate:@"UPDATE t_student SET score = 1500 WHERE name = 'zs';"];
NSArray *array = @[@"abc"];
array[1];
[db executeUpdate:@"UPDATE t_student SET score = 500 WHERE name = 'ls';"];
// 提交事务
[db commit];
}];
*/
[self.queue inTransaction:^(FMDatabase *db, BOOL *rollback) {
[db executeUpdate:@"UPDATE t_student SET score = 1500 WHERE name = 'zs';"];
NSArray *array = @[@"abc"];
// array[1];
[db executeUpdate:@"UPDATE t_student SET score = 500 WHERE name = 'ls';"];
}];
}
- (IBAction)queryOnClick
{
/*
// FMDB框架中查询用executeQuery方法
// FMResultSet结果集, 结果集其实和tablevivew很像
FMResultSet *set = [self.db executeQuery:@"SELECT id, name, score FROM t_student;"];
while ([set next]) { // next方法返回yes代表有数据可取
int ID = [set intForColumnIndex:0];
// NSString *name = [set stringForColumnIndex:1];
NSString *name = [set stringForColumn:@"name"]; // 根据字段名称取出对应的值
double score = [set doubleForColumnIndex:2];
NSLog(@"%d %@ %.1f", ID, name, score);
}
*/
[self.queue inDatabase:^(FMDatabase *db) {
// FMResultSet结果集, 结果集其实和tablevivew很像
FMResultSet *set = [db executeQuery:@"SELECT id, name, score FROM t_student;"];
while ([set next]) { // next方法返回yes代表有数据可取
int ID = [set intForColumnIndex:0];
// NSString *name = [set stringForColumnIndex:1];
NSString *name = [set stringForColumn:@"name"]; // 根据字段名称取出对应的值
double score = [set doubleForColumnIndex:2];
NSLog(@"%d %@ %.1f", ID, name, score);
}
}];
}
@end
