derby

问题 I've tried a simple code about database but it gave me this error -> ERROR: No suitable driver found for jdbc:derby:CoffeeDB;create=true package Practice; import java.sql.*; public class Practice { public static void main(String[]args)throws Exception{ final String DB_URL = "jdbc:derby:CoffeeDB;create=true"; try{ Connection conn = DriverManager.getConnection(DB_URL); Statement stmt = conn.createStatement(); String sql = ("CREATE TABLE Coffee(Description CHAR(25),Prod Num CHAR(10) NOT NULL

问题 I would like to format nicely a date received from a query like: SELECT recdate FROM myrecords; pratically I am searching the function to pretty formatting with a date pattern, better if SimpleDateFormat like. And if not possible how can I build a class for formatting with somtehing like: SELECT MyFormatter(recdate) FROM myrecords 回答1: Look here: DateFormat and SimpleDateFormat Examples Sample code: public static void main(String[] args) { // Get the Date object that comes from DerbyDB... /

问题 I have this SQL query 1 : show tables 2 : desc tablename But this doesn't seem to be the syntax in the derby. How to write these queries in derby ?? I want to check the schema of a table whether its primary key or not. How to check that in websphere 回答1: Strictly speaking, this isn't SQL. Rather, these are IJ commands, and must be processed by the IJ tool. Here's the documentation for "describe": http://db.apache.org/derby/docs/10.10/tools/rtoolsijcomrefdescribe.html And here's the

问题 In the article Using Java DB in Desktop Applications the Address Book demo have a method disconnect which have a try-catch block that catch and ignores the exception. If you add a printStackTrace you can see that the exception always occur. What's wrong here? The JavaDB should not throw this exception, or they should fix something in the example program? 回答1: Shutdown commands always raise SQLExceptions. So nothing's wrong. That's just the way Derby works. 来源： https://stackoverflow.com

问题 I have to migrate my database from MySql to Derby. However, I am facing a problem, that it is not possible just to create sql dump and import in JavaDB. Is there an easy way, a tool or something that I can use? or should I do everything by hand? Danke 回答1: One good way, is to use DdlUtils. with this, you can export a database schema from one database and create it in another. This is the MySQL page. 来源： https://stackoverflow.com/questions/25065426/easy-way-migrate-data-from-mysql-to-derby

问题 I have a class that looks something like this: @Entity public class EdgeInnovation { @Id public long id; @ManyToOne public NodeInnovation destination; @ManyToOne public NodeInnovation origin; } and another one that looks something like this: @Entity public class NodeInnovation { @Id public long id; @OneToOne public EdgeInnovation replacedEdge; } and so each table map to the other, so one entity will refer to other entities that will refer to more entities and so on, so that in the end there

问题 I'm trying to run atomically ResultSet resSet; resSet = statement.executeQuery("SELECT COUNT(*) FROM table"); resSet.next() long rowCount = resSet.getLong(1); resSet = statement.executeQuery("SELECT * FROM table"); // read data of known row count... My question is what is the best way? Currently I found out I can do: connection.setAutoCommit(false); connection.setTransactionIsolation(Connection.TRANSACTION_SERIALIZABLE) // call 2 SQL queries above connection.commit(); This way seems to work.

问题 I have an EJB3 entity bean Player which is annotated as given below: @Entity @Table(name = "PLAYER") public class Player { public Player() { super(); } @Id @GeneratedValue private String id; @Column(nullable = false) private String firstName; private String lastName; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String

问题 I use embedded Apache derby for my application. I have a SQL script called createdb.sql that creates all tables in a database and populates it with initial data, e.g.: SET SCHEMA APP; CREATE TABLE study ( study_id bigint not null GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1), name varchar(50) not null, note varchar(1000) DEFAULT '', created TIMESTAMP DEFAULT CURRENT_TIMESTAMP, deleted boolean DEFAULT false, UNIQUE(name), CONSTRAINT primary_key PRIMARY KEY (study_id) ); INSERT

问题 I'm having problems initializing my javadb network server and setting a connection to it. It's a JavaFX program. This is what I have so far: try { Class.forName("org.apache.derby.jdbc.ClientDriver").newInstance(); javadbserver = new NetworkServerControl(); javadbserver.start(null); } catch (ClassNotFoundException e) { Logger.getLogger(MainGuiController.class.getName()).log(Level.SEVERE, null, ex); System.out.println("Where is your JavaDB embedded Driver?"); return; } String dbName = "mydb";