constant.java

非常棒的java数据库

/*
 * Copyright 2004-2008 H2 Group. Licensed under the H2 License, Version 1.0
 * (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.schema;

import java.sql.SQLException;

import org.h2.engine.DbObject;
import org.h2.engine.Session;
import org.h2.expression.ValueExpression;
import org.h2.message.Message;
import org.h2.message.Trace;
import org.h2.table.Table;
import org.h2.value.Value;

/**
 * A user defined constant as created by the SQL statement
 * CREATE CONSTANT
 */
public class Constant extends SchemaObjectBase {

    private Value value;
    private ValueExpression expression;

    public Constant(Schema schema, int id, String name) {
        super(schema, id, name, Trace.SCHEMA);
    }

    public String getCreateSQLForCopy(Table table, String quotedName) {
        throw Message.getInternalError();
    }

    public String getDropSQL() {
        return null;
    }

    public String getCreateSQL() {
        StringBuffer buff = new StringBuffer();
        buff.append("CREATE CONSTANT ");
        buff.append(getSQL());
        buff.append(" VALUE ");
        buff.append(value.getSQL());
        return buff.toString();
    }

    public int getType() {
        return DbObject.CONSTANT;
    }

    public void removeChildrenAndResources(Session session) throws SQLException {
        database.removeMeta(session, getId());
        invalidate();
    }

    public void checkRename() throws SQLException {
    }

    public void setValue(Value value) {
        this.value = value;
        expression = ValueExpression.get(value);
    }

    public ValueExpression getValue() {
        return expression;
    }

}