Flex的数据基本操作（一）

想了解Flex有一段时间了，但因为对Java的不熟悉，迟迟找不到入门的感觉。近来比较忙，又常出差，再加上没有这一类的项目可做，比之前的未入门水平更有了退步。所以要写一个练手的东西，使用Flex、blazeds，用jtds连接SqlServer2005数据库，在使用过程中，有什么问题再说，开始干总比老是想要强一些。

数据库中只有两个表，一个表代表班级，另一表则保存相应的学生，在界面打开时，显示班级及学生所有数据，选择某一班级时，显示对应的学生。两个表使用外键关联。界面所提供的功能还有对学生的增删改的功能，班级的就不提供了，操作和学生相同。大概功能界面如下：

数据库结构：

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[CLASSES]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[CLASSES](
	[ID] [int] IDENTITY(1,1) NOT NULL,
	[CLASSNAME] [nvarchar](20) NOT NULL,
	[REMARK] [nvarchar](100) NULL,
 CONSTRAINT [PK_CLASS] PRIMARY KEY CLUSTERED 
(
	[ID] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
END
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[STUDENTS]') AND type in (N'U'))
BEGIN
CREATE TABLE [dbo].[STUDENTS](
	[ID] [int] IDENTITY(1,1) NOT NULL,
	[SNAME] [nvarchar](20) NOT NULL,
	[AGE] [int] NULL,
	[ADDRESS] [nvarchar](50) NULL,
	[CLASSID] [int] NOT NULL,
 CONSTRAINT [PK_STUDENTS] PRIMARY KEY CLUSTERED 
(
	[ID] ASC
)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
END
GO
IF NOT EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N'[dbo].[FK_STUDENTS_CLASS]') AND parent_object_id = OBJECT_ID(N'[dbo].[STUDENTS]'))
ALTER TABLE [dbo].[STUDENTS]  WITH CHECK ADD  CONSTRAINT [FK_STUDENTS_CLASS] FOREIGN KEY([CLASSID])
REFERENCES [dbo].[CLASSES] ([ID])
ON UPDATE CASCADE
ON DELETE CASCADE

Java与数据库的连接使用Hibernate操作，说实在话，也不太会用，只是为了图个少写代码，Hibernate.cfg.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
		"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
		"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory name="MySession">
        <property name="hibernate.connection.driver_class">net.sourceforge.jtds.jdbc.Driver</property>
        <property name="hibernate.connection.password">pwd</property>
        <property name="hibernate.connection.url">jdbc:jtds:sqlserver://localhost/test</property>
        <property name="hibernate.connection.username">sa</property>
        <property name="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</property>
		<property name="current_session_context_class">thread</property>
        
        <mapping resource="hibernate.cfg.xml"/>
        <mapping resource="com/stud/Classes.hbm.xml"/>
        <mapping resource="com/stud/Students.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

文件结构：

 

生成的Hibernate映射文件分别对应了两个表：

Classes.hbm.xml内容：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2010-6-11 13:58:04 by Hibernate Tools 3.2.4.GA -->
<hibernate-mapping>
    <class name="com.stud.Classes" table="CLASSES" schema="dbo" catalog="test">
        <id name="id" type="int">
            <column name="ID" />
            <generator class="identity" />
        </id>
        <property name="classname" type="string">
            <column name="CLASSNAME" length="20" not-null="true" />
        </property>
        <property name="remark" type="string">
            <column name="REMARK" length="100" />
        </property>
        <set name="studentses" inverse="true" lazy="false" table="STUDENTS" fetch="select">
            <key>
                <column name="CLASSID" not-null="true" />
            </key>
            <one-to-many class="com.stud.Students" />
        </set>
    </class>
</hibernate-mapping>

Students.hbm.xml内容：

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- Generated 2010-6-11 13:58:04 by Hibernate Tools 3.2.4.GA -->
<hibernate-mapping>
    <class name="com.stud.Students" table="STUDENTS" schema="dbo" catalog="test">
        <id name="id" type="int">
            <column name="ID" />
            <generator class="identity" />
        </id>
        <many-to-one name="classes" class="com.stud.Classes" fetch="select">
            <column name="CLASSID" not-null="true" />
        </many-to-one>
        <property name="sname" type="string">
            <column name="SNAME" length="20" not-null="true" />
        </property>
        <property name="age" type="java.lang.Integer">
            <column name="AGE" />
        </property>
        <property name="address" type="string">
            <column name="ADDRESS" length="50" />
        </property>
    </class>
</hibernate-mapping>