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Difference between VARCHAR2(10 CHAR) and NVARCHAR2(10)

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I've installed Oracle Database 10g Express Edition (Universal) with the default settings: SELECT * FROM NLS_DATABASE_PARAMETERS; NLS_CHARACTERSET AL32UTF8 NLS_NCHAR_CHARACTERSET AL16UTF16 Given that both CHAR and NCHAR data types seem to accept multi-byte strings, what is the exact difference between these two column definitions? VARCHAR2(10 CHAR) NVARCHAR2(10) Vincent Malgrat The NVARCHAR2 datatype was introduced by Oracle for databases that want to use Unicode for some columns while keeping another character set for the rest of the database (which uses VARCHAR2). The NVARCHAR2 is a Unicode

Is there a way to install java on Oracle 11g XE?

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问题 I am using the database Oracle 11g Express Edition (XE) and when I try to create a java source object it returns me an error: ORA-29538: Java not installed The source code is simple: create or replace and compile java source named hello AS public class Hello { public static String hello() { return "Hello!"; } }; I found at Oracle's documentation that Oracle XE does not include Java. Does anybody know if it is possible to "install" Java on it ? 回答1: No, Java support is not available in Oracle

Create user from string variables in a PL/SQL block

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问题 I use Oracle XE for the sole purpose of developing PHP applications and version 11g has apparently lost the GUI tool to manage users which 10g used to have so I'd like to prepare a code snippet to create users from command line. I'm trying to define variables so I don't need to type the same user name 16 times but I can't get the syntax right: DECLARE my_user VARCHAR2(30) := 'foo'; my_password VARCHAR2(9) := '1234'; BEGIN CREATE USER my_user IDENTIFIED BY my_password DEFAULT TABLESPACE users;

URL string format for connecting to Oracle database with JDBC

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问题 I'm a newbie to Java-related web development, and I can't seem to get a simple program with JDBC working. I'm using off-the-shelf Oracle 10g XE and the Eclipse EE IDE. From the books and web pages I've checked so far, I've narrowed the problem down to either an incorrectly written database URL or a missing JAR file. I'm getting the following error: java.sql.SQLException: No suitable driver found for jdbc:oracle://127.0.0.1:8080 with the following code: import java.sql.*; public class