Hello Seem to be a hardest word » JDBC

PreparedStatement.setTimestamp(1,datetime)

fate — Mon, 07 Apr 2008 13:19:53 +0000

Trong sqlserver có 1 cột DateTime

Trong java nếu dùng preparedStatement rồi thiết lập giá trị cho tham số cho field dateTime này thì nên dùng setTimestamp method.

Ví dụ:
// xem ky hai dong nay
java.sql.Timestamp tstamp = new java.sql.Timestamp(00-00-00);
ps.setTimestamp(5,tstamp.valueOf(“1986-04-02 00:00:00.0″));

Toàn bộ sourcecode

//http://www.roseindia.net/jdbc/jdbc-mysql/SetTimetamp.shtml


import java.sql.DriverManager;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.ResultSetMetaData;

import java.sql.Timestamp;
public class SinhVien

{

	public static void main(String args[])	throws Exception

	{

		Class.forName("sun.jdbc.odbc.JdbcOdbcDriver").newInstance();

		Connection conn = DriverManager.getConnection("jdbc:odbc:QUANLY_SINHVIEN");

		PreparedStatement ps;
		String sql="insert into tbSV(HoLot,Ten,Nu,DChi,NgSinh,NamVaoHoc,MaLop) ";

		sql+=" values(?,?,?,?,?,?,?)";

		ps = conn.prepareStatement(sql);

		ps.setString(1,"abcxyz");

		ps.setString(2,"jguru");

		ps.setBoolean(3,false);

		ps.setString(4,"Phu Nhuan");
		// xem ky hai dong nay

		Timestamp tstamp = new Timestamp(00-00-00);

		ps.setTimestamp(5,tstamp.valueOf("1986-04-02 00:00:00.0"));
		ps.setInt(6,2004);

		ps.setString(7,"TH04");

		ps.executeUpdate();
		ps = conn.prepareStatement("select * from tbSV");

		ResultSet rs = ps.executeQuery();

		viewTable(rs);
		rs.close();

		ps.close();

		conn.close();

	}

static void viewTable(ResultSet rs) throws Exception { ResultSetMetaData md = rs.getMetaData(); int n = md.getColumnCount(); while(rs.next()) { for(int i=1;i<=n;i++) System.out.printf("\t %s",rs.getString(i)); System.out.println(); } } }

Ánh xạ kiểu dữ liệu giữa SQLSERVER và Java

fate — Tue, 01 Apr 2008 14:36:09 +0000

8 Mapping SQL data types into Java

8.1 Constraints

We need to provide reasonable Java mappings for the common SQL data types. We also need to make sure that we have enough type information so that we can correctly store and retrieve parameters and recover results from SQL statements. However, there is no particular reason that the Java data type needs to be exactly isomorphic to the SQL data type. For example, since Java has no fixed length arrays, we can represent both fixed length and variable length SQL arrays as variable length Java arrays. We also felt free to use Java Strings even though they don’t precisely match any of the SQL CHAR types.

Table 2 shows the default Java mapping for various common SQL data types. Not all of these types will necessarily be supported by all databases. The various mappings are described more fully in the following sections.

SQL type	Java Type
CHAR	String
VARCHAR	String
LONGVARCHAR	String
NUMERIC	java.math.BigDecimal
DECIMAL	java.math.BigDecimal
BIT	boolean
TINYINT	byte
SMALLINT	short
INTEGER	int
BIGINT	long
REAL	float
FLOAT	double
DOUBLE	double
BINARY	byte[]
VARBINARY	byte[]
LONGVARBINARY	byte[]
DATE	java.sql.Date
TIME	java.sql.Time
TIMESTAMP	java.sql.Timestamp

Similarly table 3 shows the reverse mapping from Java types to SQL types.

Java Type	SQL type
String	VARCHAR or LONGVARCHAR
java.math.BigDecimal	NUMERIC
boolean	BIT
byte	TINYINT
short	SMALLINT
int	INTEGER
long	BIGINT
float	REAL
double	DOUBLE
byte[]	VARBINARY or LONGVARBINARY
java.sql.Date	DATE
java.sql.Time	TIME
java.sql.Timestamp	TIMESTAMP

8.2 Dynamic data access

This chapter focuses on access to results or parameters whose types are known at compile time. However, some applications, for example generic browsers or query tools, are not compiled with knowledge of the database schema they will access, so JDBC also provides support for fully dynamically typed data access. See Section 14.2.

8.3 CHAR, VARCHAR, and LONGVARCHAR

There is no need for Java programmers to distinguish among the three different flavours of SQL strings CHAR, VARCHAR, and LONGVARCHAR. These can all be expressed identically in Java. It is possible to read and write the SQL correctly without needing to know the exact data type that was expected. These types could be mapped to either String or char[]. After considerable discussion we decided to use String, as this seemed the more appropriate type for normal use. Note that the Java String class provides a method for converting a String to a char[] and a constructor for turning a char[] into a String.

For fixed length SQL strings of type CHAR(n), the JDBC drivers will perform appropriate padding with spaces. Thus when a CHAR(n) field is retrieved from the database the resulting String will always be of length “n” and may include some padding spaces at the end. When a String is sent to a CHAR(n) field, the driver and/or the database will add any necessary padding spaces to the end of the String to bring it up to length “n”.

The ResultSet.getString method allocates and returns a new String. This is suitable for retrieving normal data, but the LONGVARCHAR SQL type can be used to store multi-megabyte strings. We therefore needed to provide a way for Java programmers to retrieve a LONGVARCHAR value in chunks. We handle this by allowing programmers to retrieve a LONGVARCHAR as a Java input stream from which they can subsequently read data in whatever chunks they prefer. Java streams can be used for either Unicode or Ascii data, so the programmer may chose to use either getAsciiStream or getUnicodeStream.

8.4 DECIMAL and NUMERIC

The SQL DECIMAL and NUMERIC data types are used to express fixed point numbers where absolute precision is required. They are often used for currency values. These two types can be expressed identically in Java. The most convenient mapping uses the java.math.BigDecimal extended precision number type provided in JDK1.1

We also allow access to DECIMAL and NUMERIC as simple Strings and arrays of chars. Thus Java programmers can use getString to receive a NUMERIC or DECIMAL result.

8.5 BINARY, VARBINARY, and LONGVARBINARY

There is no need for Java programmers to distinguish among the three different flavours of SQL byte arrays BINARY, VARBINARY, and LONGVARBINARY. These can all be expressed identically as byte arrays in Java. (It is possible to read and write the SQL correctly without needing to know the exact BINARY data type that was expected.) As with the LONGVARCHAR SQL type, the LONGVARBINARY SQL type can sometimes be used to return multi-megabyte data values. We therefore allow a LONGVARBINARY value to be retrieved as a Java input stream, from which programmers can subsequently read data in whatever chunks they prefer.

8.6 BIT

The SQL BIT type can be mapped directly to the Java boolean type.

8.7 TINYINT, SMALLINT, INTEGER, and BIGINT

The SQL TINYINT, SMALLINT, INTEGER, and BIGINT types represent 8 bit, 16 bit, 32 bit, and 64 bit values. These therefore can be mapped to Java’s byte, short, int, and long data types.

8.8 REAL, FLOAT, and DOUBLE

SQL defines three floating point data types, REAL, FLOAT, and DOUBLE. We map REAL to Java float, and FLOAT and DOUBLE to Java double.

REAL is required to support 7 digits of mantissa precision. FLOAT and DOUBLE are required to support 15 digits of mantissa precision.

8.9 DATE, TIME, and TIMESTAMP

SQL defines three time related data types. DATE consists of day, month, and year. TIME consists of hours, minutes and seconds. TIMESTAMP combines DATE and TIME and also adds in a nanosecond field. There is a standard Java class java.util.Date that provides date and time information. However, this class doesn’t perfectly match any of the three SQL types, as it includes both DATE and TIME information, but lacks the nanosecond granularity required for TIMESTAMP.

We therefore define three subclasses of java.util.Date. These are:

java.sql.Date for SQL DATE information
java.sql.Time for SQL TIME information
java.sql.Timestamp for SQL TIMESTAMP information

In the case of java.sql.Date the hour, minute, second, and milli-second fields of the java.util.Date base class are set to zero. In the case of java.sql.Time the year, month, and day fields of the java.util.Date base class are set to 1970, January, and 1, respectively. This is the “zero” date in the Java epoch.

The java.sql.Timestamp class extends java.util.Date by adding a nanosecond field.

theo nguồn java.sun.com tutorial

Cài đặt – Cấu hình – Sử dụng JavaDB (derby)

fate — Sun, 30 Mar 2008 05:27:52 +0000

http://www.netbeans.org/kb/60/ide/java-db.html

http://java.sun.com/developer/technicalArticles/J2SE/Desktop/javadb/

Netbeans Database Application tutorial

fate — Sun, 30 Mar 2008 04:21:21 +0000

http://www.netbeans.org/kb/60/java/gui-db.html

http://www.netbeans.org/kb/60/java/gui-binding.html

ElegantJ Data Tables JAVABean

fate — Sun, 30 Mar 2008 00:17:01 +0000

ElegantJ Data Tables JAVABean

Ready to use Table component that has all you wished to have

Be it a 4 row by 10 column table or a table to represent a database in tabular form, or a spreadsheet solution, you can rely on ElegantJ Data Tables Bean. From AWT Data Table and JFC Data Table, select the one that suits your need. Both can handle large volume of data. Get the data filled directly from data source. A cell can be edited as a Textbox, Text Area, Checkbox, Combo box, a Button, an icon, Boolean, etc. Manage data with maximum flexibility using Bean’s formatting, editing, navigating and data handling features. Ready to use Search Panel, functions of insert, add or delete a row as well as column and sorting.

ElegantJ Data Tables Bean offers total control over data management through table.

For small table as well as large tables
AWT and JFC components
Insert, Delete or Change a row
Control editability at row / column or table level
Data access from a database, text or an XML file
Supports JDBC and protocols like FILE, FTP and HTTP for interfacing with data source
Highly flexible and configurable
Page setup and printing features
Ready to use search panel, sort and right-click menu

Efficient Data handling
Data Access Beans that are shipped with this bean are so powerful and flexible; they can work in most of the limitations imposed by architectural circumstances, security and accessibility constraints on servers. With ElegantJ Data Access Bean, you will be able connect and communicate with any computer through protocols like FILE, JDBC, FTP or HTTP.

Java™ Library
ElegantJBeans is a collection of JavaBeans™ Components developed for Java professionals. Development platform is not a constraint for ElegantJBeans. You can use ElegantJBeans component with J2SE, J2EE, Java applications and Java applets. ElegantJBeans can be imported in all major IDEs – to use it visually as well as through coding.

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Data Table Components in Sun Java(TM) Studio Creator 2

fate — Sun, 30 Mar 2008 00:11:20 +0000

Background

Sun Java Studio Creator 2 introduced new “basic” components to the Palette, while retaining the JavaServer Faces components the previous version, called “standard” components.

This technical tip explains how to bind a database table (that you have dropped on a page in the Java Studio Creator 2 IDE) to a Data Table component, which is a standard component from the previous version of the IDE, Java Studio Creator 2004Q2. Standard components have been maintained in Java Studio Creator 2 so that pages from projects developed with Java Studio Creator 2004Q2 can work without modifications. You can find these standard components on the Palette in the Standard section.

In Java Studio Creator 2, data provider components bind the Table component to a database table. That is, when you drop a database table on a Table component on a page, the IDE uses a data provider to bind the Table component to the database table.

If you use a Data Table component from the Standard section of the Palette, the Data Table component cannot be bound to the database table using a data provider. However, by manually binding the component to the database table, it is possible to create pages that use both standard components and basic components. Follow the instructions below to bind a database table to a Standard Data Table component.

Chary Kanaparthi is a member of the Quality Engineering team for Java Studio Creator.

Binding a Data Table Component to a Database Table

You can bind a Data Table component to a database table using the Table Layout dialog. You actually bind the Data Table component to the database table’s RowSet. Follow the steps outlined here to see how this is accomplished.

Drop a Data Table from the Standard section of the Palette on to a page in the Design window.
Add a database table to the page. In the Servers window, right-click a database table from the Data Sources node and select Add to Page from the context menu.
Select the Data Table component. You can select the component in the Outline window or on the Design window page. Right-click to bring up its context menu and click Table Layout.
From the Table Layout dialog, select the appropriate RowSet for the Get data from: prompt. Click OK. Figure 1 shows personRowSet selected from the dropdown list.

Figure 1: Bind Table to RowSet

After the operation completes, the Data Table component on the page changes to reflect the binding to the database table. The Data Table is now bound to the PERSON database table, personRowSet, as shown in Figure 2.

Figure 2: Standard Data Table Component After Binding

More Developer Resources

For more tech tips, articles, forums, tutorials, weblogs, and other expert advice for developers, visit the Java Studio Creator developer resources on the Sun Developer Network (SDN) at http://developers.sun.com/jscreator/

Cập nhật dữ liệu vào CSDL thông qua trung gian ResultSet

fate — Thu, 27 Mar 2008 09:02:59 +0000

Table Mônhọc(MaMon,TenMon,SoTiet)

// Lấy về ResultSet từ table Môn
String s_sql = “select * from tbMon”;
Statement stat = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
ResultSet rs = stat.executeQuery(s_sql);
// Cập nhật dữ lịêu không cần viết t-sql
rs.absolute(row_id); // đi đến dòng thứ row_id trong ResultSet
rs.updateString(“TenMon”,tenmon); // update tên môn vào ResultSet
rs.updateInt(“SoTiet”,sotiet); // update số tiết vào ResultSet
rs.updateRow(); // cập nhật vào CSDL

// Xoá dữ lịêu không cần viết t-sql
rs.absolute(row_id); // đi đến dòng thứ row_id trong ResultSet
rs.deleteRow(); xoá dòng đó trong CSDL

// Thêm dữ lịêu không cần viết t-sql
rs.moveToInsertRow(); // nhảy sang 1 dòng trống để thêm
rs.updateString(“MaMon”,ma_mon); // thêm mã môn vào ResultSet
rs.updateString(“TenMon”,ten_mon); // thêm tên môn vào ResultSet
rs.updateInt(“SoTiet”,so_tiet); // thêm số tiết vào ResultSet
rs.insertRow(); // thêm bộ dữ liệu đó vào CSDL
rs.moveToCurrentRow(); //

Nói thêm về Row_ID:
- Dòng đầu tiên trong ResultSet sẽ có Row_ID = 1
- Ví dụ:
// lấy về ResultSet
while(rs.next())
{
rs.getString(1); // ỏ lần loop đầu tiên của while, rs sẽ trỏ vào dòng có Row_ID = 1 (dòng đầu tiên trong table trong CSDL)
}

Nói thêm về Col_ID
- Cột đầu tiên trong ResultSetMetaData sẽ có Col_ID = 1
- Ví dụ:
// lấy về ResultSetMetaData md= rs.getMetaData();
for(int i=1;i<=md.getColumnCount();i++)
md.getColumnName(1); // lần loop đầu tiên, metadata sẽ trỏ vào cột có Col_ID = 1 (cột đầu tiên trong table trong CSDL)

Lập Trình Csdl Java-postgresql

fate — Tue, 25 Mar 2008 12:15:14 +0000

DẠO ĐẦU:
JAVA LÀ 1 NGÔN NGỮ – CÔNG NGHỆ LT LÂU ĐỜI , ỔN ĐỊNH. NÓ CÓ THỂ LÀM VIỆC VỚI NHIỀU HỆ QTCSDL KHÁC NHAU NHƯ ORACLE,SQLSERVER,MYSQL,POSGRESQL (THỰC TẾ CÁC CTY CHUỘNG CÁC LOẠI DBMS NÀY NHẤT TRONG SỐ CÁC DBMS)

ORACLE,SQLSERVER,MYSQL ĐA ĐƯỢC NHIỀU NGƯỜI BIẾT ĐẾN, VẬY MINH SẼ HƯỚNG DẪN CÁC BẠN LẬP TRÌNH CSDL TỪ JAVA -> POSGRESQL

ĐIỀU KIỆN CẦN ĐỂ CÓ THỄ THỰC HÀNH CÁC THAO TÁC TRONG BÀI NÀY:

1/ CƠ BẢN JAVA
2/ CƠ BẢN LÝ THUYẾT LẬP TRÌNH CSDL JAVA
3/ CƠ BẢN POSGRESQL HOẶC THAM KHẢO BÀI VIẾT VỀ POSTGRE CŨNG Ở TRONG BLOG NÀY

CÔNG CỤ SỬ DỤNG TRONG BÀI VIẾT NÀY:

TRÌNH CÔNG CỤ TIỆN ÍCH PHÁT TRIỂN JAVA: J2SE5.0/JDK1.5 (NÊN LÀ VERSION NÀY ĐỂ TUONG THÍCH VỚI DRIVER CỦA POSTGRESQL DƯỚI ĐÂY)
www.java.sun.com

bộ cài postgresql (msi), cũng có thể down bộ no-install.zip (tìm trên postgresql.org)

QUOTE

http://ftp4.tw.postgresql.org/binary/v8.2….sql-8.2.6-2.zip

driver của postgresql để lập trình java với jdbc

QUOTE

http://jdbc.postgresql.org/download/postgr…2-507.jdbc3.jar

tài lịeu sử dụng driver trên

QUOTE

http://jdbc.postgresql.org/documentation/p…c-82-doc.tar.gz

THỰC HÀNH:

Cần có 1 database trước khi dịch và chạy file này. Các bạn nên tham khảo thêm topic: http://kiamiracle.wordpress.com/2008/02/09/th%e1%bb%ac-s%e1%bb%a8c-v%e1%bb%9ai-1-h%e1%bb%86-qt-csdl-m%e1%bb%9ai-postgresql/

1> Cấu trúc ứng dụng: các file sau để cùng 1 thư mục
–postgresql-8.2-507.jdbc3.jar -> đây là driver của postgres cho jdbc mà bạn dowload về
–TestConnection.java
–runit.bat

Cài đặt jdk1.5 để thực hành (tự tìm hiểu)- tham khảo trên www.javavietnam.org là tốt nhất

2> jdk_home
- Giả sử đây là thư mục bin của jdk đã cài:
C:\Program Files\Java\jdk1.5.0_14\bin

3> Mã nguồn file TestConnection.java

QUOTE

import java.sql.*;public class TestConnection
{
public static void main(String args[]) throws Exception
{
System.out.println(“Hello World”);
Class.forName(“org.postgresql.Driver”); // đăng ký driver
String url = “jdbc:postgresql://localhost:5432/QLVT?user=postgres&password=shushi”;
// QLVT là tên db đó// thiết lập kết nối
Connection conn = DriverManager.getConnection(url);Statement st = conn.createStatement();
ResultSet rs = st.executeQuery(“SELECT * FROM \”DanhMucVatTu\”");
while (rs.next())
{
System.out.println(rs.getString(1)+”——-”+rs.getString(2));
}
rs.close();
st.close();}
}

4> Nội dung file runit.bat

set path=.;C:\Program Files\Java\jdk1.5.0_14\bin
javac TestConnection.java
set CLASSPATH=.;postgresql-8.2-507.jdbc3.jar
java TestConnection
@pause

*** FINAL: CHẠY FILE RUNIT.BAT VÀ CẢM NHẬN

http://kiamiracle.wordpress.com/2008/02/09/th%e1%bb%ac-s%e1%bb%a8c-v%e1%bb%9ai-1-h%e1%bb%86-qt-csdl-m%e1%bb%9ai-postgresql/

CÔNG CỤ SỬ DỤNG TRONG BÀI VIẾT NÀY:

TRÌNH CÔNG CỤ TIỆN ÍCH PHÁT TRIỂN JAVA: J2SE5.0/JDK1.5 (NÊN LÀ VERSION NÀY ĐỂ TUONG THÍCH VỚI DRIVER CỦA POSTGRESQL DƯỚI ĐÂY)
www.java.sun.com

bộ cài postgresql (msi), cũng có thể down bộ no-install.zip (tìm trên postgresql.org)

QUOTE

http://ftp4.tw.postgresql.org/binary/v8.2….sql-8.2.6-2.zip

driver của postgresql để lập trình java với jdbc

QUOTE

http://jdbc.postgresql.org/download/postgr…2-507.jdbc3.jar

tài lịeu sử dụng driver trên

QUOTE

http://jdbc.postgresql.org/documentation/p…c-82-doc.tar.gz