constraint.java

一个用java写的开源的数据库系统

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package org.hsqldb;

import org.hsqldb.lib.ArrayUtil;
import java.sql.SQLException;

// fredt@users 20020225 - patch 1.7.0 by boucherb@users - named constraints
// fredt@users 20020320 - doc 1.7.0 - update
// tony_lai@users 20020820 - patch 595156 by tlai@users -  violation of Integrity constraint name

/**
 *  Implementation of a table constraint with references to the indexes used
 *  by the constraint.
 *
 * @version    1.7.0
 */
class Constraint {

    static final int       FOREIGN_KEY = 0,
                           MAIN        = 1,
                           UNIQUE      = 2;
    private ConstraintCore core;
    private HsqlName       constName;
    private int            iType;

    /**
     *  Constructor declaration
     *
     * @param  name
     * @param  t
     * @param  index
     */
    Constraint(HsqlName name, Table t, Index index) {

        core       = new ConstraintCore();
        constName  = name;
        iType      = UNIQUE;
        core.tMain = t;
        core.iMain = index;
        /* fredt - in unique constraints column list for iColMain is that
           of iMain
        */
        core.iColMain = index.getColumns();
        core.iLen     = core.iColMain.length;
    }

    /**
     *  Constructor for main constraints (foreign key references in PK table)
     *
     * @param  name
     * @param  t
     * @param  index
     */
    Constraint(HsqlName name, Constraint fkconstraint) {

        constName = name;
        iType     = MAIN;
        core      = fkconstraint.core;
    }

    /**
     *  Constructor for foreign key constraints
     *
     * @param  pkname
     * @param  fkname
     * @param  main
     * @param  ref
     * @param  colmain
     * @param  colref
     * @param  imain
     * @param  iref
     * @exception  SQLException  Description of the Exception
     */
    Constraint(HsqlName pkname, HsqlName fkname, Table main, Table ref,
               int colmain[], int colref[], Index imain, Index iref,
               boolean cascade) throws SQLException {

        core        = new ConstraintCore();
        core.pkName = pkname;
        core.fkName = fkname;
        constName   = fkname;
        iType       = FOREIGN_KEY;
        core.tMain  = main;
        core.tRef   = ref;
        /* fredt - in FK constraints column lists for iColMain and iColRef have
           identical sets to visible columns of iMain and iRef respectively
           but the order of columns can be different and must be maintained
        */
        core.iColMain = colmain;
        core.iLen     = core.iColMain.length;
        core.iColRef  = colref;
        core.oColRef  = new Object[core.iColRef.length];
        core.iMain    = imain;
        core.iRef     = iref;
        core.bCascade = cascade;

        setTableRows();
    }

    private Constraint() {}

    private void setTableRows() throws SQLException {

        core.oMain = core.tMain.getNewRow();

        if (core.tRef != null) {
            core.oRef = core.tRef.getNewRow();
        }

        if (Trace.DOASSERT) {
            Trace.doAssert(core.iColMain.length == core.iColRef.length);
        }
    }

    HsqlName getName() {
        return constName;
    }

    /**
     * Changes constraint name.
     *
     * @param name
     * @param isquoted
     */
    private void setName(String name, boolean isquoted) {
        constName.rename(name, isquoted);
    }

    /**
     *  probably a misnomer, but DatabaseMetaData.getCrossReference specifies
     *  it this way (I suppose because most FKs are declared against the PK of
     *  another table)
     *
     *  @return name of the index refereneced by a foreign key
     */
    String getPkName() {
        return core.pkName == null ? null
                                   : core.pkName.name;
    }

    /**
     *  probably a misnomer, but DatabaseMetaData.getCrossReference specifies
     *  it this way (I suppose because most FKs are declared against the PK of
     *  another table)
     *
     *  @return name of the index for the referencing foreign key
     */
    String getFkName() {
        return core.fkName == null ? null
                                   : core.fkName.name;
    }

    /**
     *  Method declaration
     *
     * @return name of the index for the foreign key column (child)
     */
    int getType() {
        return iType;
    }

    /**
     *  Method declaration
     *
     * @return
     */
    Table getMain() {
        return core.tMain;
    }

    Index getMainIndex() {
        return core.iMain;
    }

    /**
     *  Method declaration
     *
     * @return
     */
    Table getRef() {
        return core.tRef;
    }

    Index getRefIndex() {
        return core.iRef;
    }

    /**
     *  Does (foreign key) constraint cascade on delete
     *
     * @return
     */
    boolean isCascade() {
        return core.bCascade;
    }

    /**
     *  Method declaration
     *
     * @return