Quadcap Embeddable Database

com/quadcap/sql/meta/MetaColumns.java

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package com.quadcap.sql.meta;

/* Copyright 1999 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.IOException;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Vector;

import java.sql.ResultSetMetaData;
import java.sql.SQLException;

import com.quadcap.sql.Column;
import com.quadcap.sql.Database;
import com.quadcap.sql.Expression;
import com.quadcap.sql.Relation;
import com.quadcap.sql.Row;
import com.quadcap.sql.Session;
import com.quadcap.sql.StaticCursor;
import com.quadcap.sql.Table;

import com.quadcap.sql.index.BCursor;
import com.quadcap.sql.index.Btree;

import com.quadcap.sql.types.*;

import com.quadcap.util.Debug;

/**
 * A Cursor supporting the <code>DatabaseMetaData.getColumns()</code>
 * operation.
 *
 * @author Stan Bailes
 */
public class MetaColumns extends MetaCursor {
    static Column[] cols = {
        new Column("TABLE_CAT", typeString),            // 1
        new Column("TABLE_SCHEM", typeString),          // 2 
        new Column("TABLE_NAME", typeString),           // 3
        new Column("COLUMN_NAME", typeString),          // 4
        new Column("DATA_TYPE", typeShort),             // 5
        new Column("TYPE_NAME", typeString),            // 6
        new Column("COLUMN_SIZE", typeInt),             // 7
        new Column("BUFFER_LENGTH", typeAny),           // 8
        new Column("DECIMAL_DIGITS", typeInt),          // 9
        new Column("NUM_PREC_RADIX", typeInt),          // 10
        new Column("NULLABLE", typeInt),                // 11
        new Column("REMARKS", typeString),              // 12
        new Column("COLUMN_DEF", typeString),           // 13
        new Column("SQL_DATA_TYPE", typeInt),           // 14
        new Column("SQL_DATETIME_SUB", typeInt),        // 15
        new Column("CHAR_OCTET_LENGTH", typeInt),       // 16
        new Column("ORDINAL_POSITION", typeInt),        // 17
        new Column("IS_NULLABLE", typeString)           // 18
    };

    static int[] sortColumns = { 2, 3, 17 };

    public MetaColumns(Session session, Expression predicate)
        throws SQLException
    {
        super(session, predicate);
        try {
            addColumns(cols);
            Database db = session.getDatabase();
            session.getTableWriteLock("#Schema");
            synchronized (db.getFile().getLock()) {
                Iterator iter = db.getRelationNameIterator();
                while (iter.hasNext()) {
                    Relation r = db.getRelation(iter.next().toString());
                    if (r instanceof Table) {
                        Table t = (Table)r;
                        doTable(t);
                    }
                }
            }
            sort();
        } catch (ValueException e) {
            Debug.print(e);
            SQLException te = new SQLException(e.toString(), "Q000J");
            te.setNextException(e);
            throw te;
        } catch (IOException e) {
            Debug.print(e);
            throw new SQLException(e.toString(), "Q000K");
        }           
    }

    public int[] getSortColumns() {
        return sortColumns;
    }

    void doTable(Table t) throws SQLException {
        for (int i = 1; i <= t.getColumnCount(); i++) {
            Column col = t.getColumn(i);
            Row row = doColumn(t, col);
            if (rowMatch(row)) {
                addRow(row);
            }
        }
    }

    Row doColumn(Table t, Column col) throws SQLException {
        Type type = col.getType();
        Row row = new Row(18);
        row.set(1, ValueNull.valueNull);
        doTableName(2, row, t.getName());
        row.set(4, new ValueString(col.getShortName()));
        row.set(5, new ValueShort(type.getJDBCType()));
        row.set(6, new ValueString(type.getTypeName()));

        Value size = new ValueInteger(type.getPrecision());
        if (type instanceof TypeChar) {
            size = new ValueInteger(((TypeChar)type).getMax());
        } else if (type instanceof TypeVarChar) {
            size = new ValueInteger(((TypeVarChar)type).getMax());
        } 
        row.set(7, size);
        row.set(8, ValueNull.valueNull);
        row.set(9, new ValueInteger(type.getScale()));
        row.set(10, new ValueInteger(10));
        row.set(11, new ValueInteger(col.getNullable()));
        row.set(12, ValueNull.valueNull);
        Value defVal = ValueNull.valueNull;
        Expression def = col.getDefault();
        if (def != null) {
            defVal = new ValueString(def.toString());
        }
        row.set(13, defVal);
        row.set(14, ValueNull.valueNull);
        row.set(15, ValueNull.valueNull);

        Value max = ValueNull.valueNull;
        if (type instanceof TypeChar) {
            max = new ValueInteger(2 * ((TypeChar)type).getMax());
        } else if (type instanceof TypeVarChar) {
            max = new ValueInteger(2 * ((TypeVarChar)type).getMax());
        } 
        row.set(16, max);
        row.set(17, new ValueInteger(col.getColumn()));

        String nullstr = "";
        switch (col.getNullable()) {
        case ResultSetMetaData.columnNoNulls:
            nullstr = "NO";
            break;
        case ResultSetMetaData.columnNullable:
            nullstr = "YES";
            break;
        }
        row.set(18, new ValueString(nullstr));
        return row;
    }

}