databaseinformationmain.java

hsql是很有名的嵌入式数据库

     *
     * Given the above definitions, the rules currently in effect for reporting
     * best row identifier are as follows, in order of precedence: <p>
     *
     * <OL>
     * <LI> if the table under consideration has a primary key contraint, then
     *      the columns of the primary key are reported, with no consideration
     *      given to the column set performance ranking over the set of
     *      candidate keys. Each row has its IN_KEY column set to TRUE.
     *
     * <LI> if 1.) does not hold, then if there exits one or more alternate
     *      keys, then the columns of the alternate key with the lowest column
     *      count are reported, with no consideration given to the column set
     *      performance ranking over the set of candidate keys. If there
     *      exists a tie for lowest column count, then the columns of the
     *      first such key encountered are reported.
     *      Each row has its IN_KEY column set to TRUE.
     *
     * <LI> if both 1.) and 2.) do not hold, then, if possible, a unique
     *      contraint/index is selected from the set of unique
     *      contraints/indices containing at least one column having
     *      a not null constraint, with no consideration given to the
     *      column set performance ranking over the set of all such
     *      candidate column sets. If there exists a tie for lowest non-zero
     *      count of columns having a not null constraint, then the columns
     *      of the first such encountered candidate set are reported. Each
     *      row has its IN_KEY column set to FALSE. <p>
     *
     * <LI> Finally, if the set of candidate column sets in 3.) is the empty,
     *      then no column set is reported for the table under consideration.
     * </OL> <p>
     *
     * The scope reported for a best row identifier column set is determined
     * thus: <p>
     *
     * <OL>
     * <LI> if the database containing the table under consideration is in
     *      read-only mode or the table under consideration is GLOBAL TEMPORARY
     *      (a TEMP or TEMP TEXT table, in HSQLDB parlance), then the scope
     *      is reported as
     *      <code>java.sql.DatabaseMetaData.bestRowSession</code>.
     *
     * <LI> if 1.) does not hold, then the scope is reported as
     *      <code>java.sql.DatabaseMetaData.bestRowTemporary</code>.
     * </OL> <p>
     *
     * @return a <code>Table</code> object describing the optimal
     * set of visible columns that uniquely identifies a row
     * for each accessible table defined within this database
     * @throws HsqlException if an error occurs while producing the table
     */
    final Table SYSTEM_BESTROWIDENTIFIER() throws HsqlException {

        Table t = sysTables[SYSTEM_BESTROWIDENTIFIER];

        if (t == null) {
            t = createBlankTable(sysTableHsqlNames[SYSTEM_BESTROWIDENTIFIER]);

            addColumn(t, "SCOPE", Types.SMALLINT, false);            // not null
            addColumn(t, "COLUMN_NAME", Types.VARCHAR, false);       // not null
            addColumn(t, "DATA_TYPE", Types.SMALLINT, false);        // not null
            addColumn(t, "TYPE_NAME", Types.VARCHAR, 32, false);     // not null
            addColumn(t, "COLUMN_SIZE", Types.INTEGER);
            addColumn(t, "BUFFER_LENGTH", Types.INTEGER);
            addColumn(t, "DECIMAL_DIGITS", Types.SMALLINT);
            addColumn(t, "PSEUDO_COLUMN", Types.SMALLINT, false);    // not null
            addColumn(t, "TABLE_CAT", Types.VARCHAR);
            addColumn(t, "TABLE_SCHEM", Types.VARCHAR);
            addColumn(t, "TABLE_NAME", Types.VARCHAR, false);        // not null
            addColumn(t, "NULLABLE", Types.SMALLINT, false);         // not null
            addColumn(t, "IN_KEY", Types.BOOLEAN, false);            // not null

            // order: SCOPE
            // for unique:  TABLE_CAT, TABLE_SCHEM, TABLE_NAME, COLUMN_NAME
            // false PK, as TABLE_CAT and/or TABLE_SCHEM may be null
            t.createPrimaryKey(null, new int[] {
                0, 8, 9, 10, 1
            }, false);

            return t;
        }

        // calculated column values
        Integer scope;           // { temp, transaction, session }
        Integer pseudo;

        //-------------------------------------------
        // required for restriction of results via
        // DatabaseMetaData filter parameters, but
        // not actually required to be included in
        // DatabaseMetaData.getBestRowIdentifier()
        // result set
        //-------------------------------------------
        String  tableCatalog;    // table calalog
        String  tableSchema;     // table schema
        String  tableName;       // table name
        Boolean inKey;           // column participates in PK or AK?

        //-------------------------------------------
        // TODO:  Maybe include:
        //        - backing index (constraint) name?
        //        - column sequence in index (constraint)?
        //-------------------------------------------
        // Intermediate holders
        Iterator       tables;
        Table          table;
        DITableInfo    ti;
        int[]          cols;
        Object[]       row;
        HsqlProperties p;

        // Column number mappings
        final int iscope          = 0;
        final int icolumn_name    = 1;
        final int idata_type      = 2;
        final int itype_name      = 3;
        final int icolumn_size    = 4;
        final int ibuffer_length  = 5;
        final int idecimal_digits = 6;
        final int ipseudo_column  = 7;
        final int itable_cat      = 8;
        final int itable_schem    = 9;
        final int itable_name     = 10;
        final int inullable       = 11;
        final int iinKey          = 12;

        // Initialization
        ti     = new DITableInfo();
        p      = database.getProperties();
        tables = p.isPropertyTrue("hsqldb.system_table_bri") ? allTables()
                                                             : database
                                                             .schemaManager
                                                                 .allTablesIterator();

        // Do it.
        while (tables.hasNext()) {
            table = (Table) tables.next();

            if (table.isView() ||!isAccessibleTable(table)) {
                continue;
            }

            cols = table.getBestRowIdentifiers();

            if (cols == null) {
                continue;
            }

            ti.setTable(table);

            inKey = ValuePool.getBoolean(table.isBestRowIdentifiersStrict());
            tableCatalog = ns.getCatalogName(table);
            tableSchema  = table.getSchemaName();
            tableName    = ti.getName();
            scope        = ti.getBRIScope();
            pseudo       = ti.getBRIPseudo();

            for (int i = 0; i < cols.length; i++) {
                row                  = t.getEmptyRowData();
                row[iscope]          = scope;
                row[icolumn_name]    = ti.getColName(i);
                row[idata_type]      = ti.getColDataType(i);
                row[itype_name]      = ti.getColDataTypeName(i);
                row[icolumn_size]    = ti.getColSize(i);
                row[ibuffer_length]  = ti.getColBufLen(i);
                row[idecimal_digits] = ti.getColScale(i);
                row[ipseudo_column]  = pseudo;
                row[itable_cat]      = tableCatalog;
                row[itable_schem]    = tableSchema;
                row[itable_name]     = tableName;
                row[inullable]       = ti.getColNullability(i);
                row[iinKey]          = inKey;

                t.insertSys(row);
            }
        }

        t.setDataReadOnly(true);

        return t;
    }

    /**
     * Retrieves a <code>Table</code> object naming the accessible catalogs
     * defined within this database. <p>
     *
     * Each row is a catalog name description with the following column: <p>
     *
     * <pre class="SqlCodeExample">
     * TABLE_CAT   VARCHAR   catalog name
     * </pre> <p>
     *
     * @return a <code>Table</code> object naming the accessible
     *        catalogs defined within this database
     * @throws HsqlException if an error occurs while producing the table
     */
    final Table SYSTEM_CATALOGS() throws HsqlException {

        Table t = sysTables[SYSTEM_CATALOGS];

        if (t == null) {
            t = createBlankTable(sysTableHsqlNames[SYSTEM_CATALOGS]);

            addColumn(t, "TABLE_CAT", Types.VARCHAR, false);    // not null

            // order:  TABLE_CAT
            // true PK
            t.createPrimaryKey(null, new int[]{ 0 }, true);

            return t;
        }

        Object[] row;
        Iterator catalogs;

        catalogs = ns.iterateCatalogNames();

        while (catalogs.hasNext()) {
            row    = t.getEmptyRowData();
            row[0] = (String) catalogs.next();

            t.insertSys(row);
        }

        t.setDataReadOnly(true);

        return t;
    }

    /**
     * Retrieves a <code>Table</code> object describing the visible
     * access rights for all visible columns of all accessible
     * tables defined within this database.<p>
     *
     * Each row is a column privilege description with the following
     * columns: <p>
     *
     * <pre class="SqlCodeExample">
     * TABLE_CAT    VARCHAR   table catalog
     * TABLE_SCHEM  VARCHAR   table schema
     * TABLE_NAME   VARCHAR   table name
     * COLUMN_NAME  VARCHAR   column name
     * GRANTOR      VARCHAR   grantor of access
     * GRANTEE      VARCHAR   grantee of access
     * PRIVILEGE    VARCHAR   name of access
     * IS_GRANTABLE VARCHAR   grantable?: "YES" - grant to others, else "NO"
     * </pre>
     *
     * <b>Note:</b> As of 1.7.2, HSQLDB does not support column level
     * privileges. However, it does support table-level privileges, so they
     * are reflected here.  That is, the content of this table is equivalent
     * to a projection of SYSTEM_TABLEPRIVILEGES and SYSTEM_COLUMNS joined by
     * full table identifier. <p>
     *
     * @return a <code>Table</code> object describing the visible
     *        access rights for all visible columns of
     *        all accessible tables defined within this
     *        database
     * @throws HsqlException if an error occurs while producing the table
     */
    final Table SYSTEM_COLUMNPRIVILEGES() throws HsqlException {

        Table t = sysTables[SYSTEM_COLUMNPRIVILEGES];

        if (t == null) {
            t = createBlankTable(sysTableHsqlNames[SYSTEM_COLUMNPRIVILEGES]);

            addColumn(t, "TABLE_CAT", Types.VARCHAR);
            addColumn(t, "TABLE_SCHEM", Types.VARCHAR);
            addColumn(t, "TABLE_NAME", Types.VARCHAR, false);         // not null
            addColumn(t, "COLUMN_NAME", Types.VARCHAR, false);        // not null
            addColumn(t, "GRANTOR", Types.VARCHAR, false);            // not null
            addColumn(t, "GRANTEE", Types.VARCHAR, false);            // not null
            addColumn(t, "PRIVILEGE", Types.VARCHAR, 10, false);      // not null
            addColumn(t, "IS_GRANTABLE", Types.VARCHAR, 3, false);    // not null

            // order: COLUMN_NAME, PRIVILEGE
            // for unique: GRANTEE, GRANTOR, TABLE_NAME, TABLE_SCHEM, TABLE_CAT
            // false PK, as TABLE_SCHEM and/or TABLE_CAT may be null
            t.createPrimaryKey(null, new int[] {
                3, 6, 5, 4, 2, 1, 0
            }, false);

            return t;
        }

        Result rs;

        // - saves ~ 100 bytes jar space
        rs = session.sqlExecuteDirectNoPreChecks(
            "select a.TABLE_CAT, a.TABLE_SCHEM, a.TABLE_NAME, b.COLUMN_NAME, "
            + "a.GRANTOR, a.GRANTEE, a.PRIVILEGE, a.IS_GRANTABLE "
            + "from  INFORMATION_SCHEMA.SYSTEM_TABLEPRIVILEGES a, INFORMATION_SCHEMA.SYSTEM_COLUMNS b where a.TABLE_NAME = b.TABLE_NAME;");

        t.insertSys(rs);
        t.setDataReadOnly(true);

        return t;
    }

    /**
     * Retrieves a <code>Table</code> object describing the
     * visible columns of all accessible tables defined
     * within this database.<p>
     *
     * Each row is a column description with the following columns: <p>
     *
     * <pre class="SqlCodeExample">
     * TABLE_CAT         VARCHAR   table catalog
     * TABLE_SCHEM       VARCHAR   table schema
     * TABLE_NAME        VARCHAR   table name
     * COLUMN_NAME       VARCHAR   column name
     * DATA_TYPE         SMALLINT  SQL type from DITypes
     * TYPE_NAME         VARCHAR   canonical type name
     * COLUMN_SIZE       INTEGER   column size (length/precision)
     * BUFFER_LENGTH     INTEGER   transfer size in bytes, if definitely known
     * DECIMAL_DIGITS    INTEGER   # of fractional digits (scale)
     * NUM_PREC_RADIX    INTEGER   Radix
     * NULLABLE          INTEGER   is NULL allowed? (from DatabaseMetaData)
     * REMARKS           VARCHAR   comment describing column
     * COLUMN_DEF        VARCHAR   default value (possibly expression)
     * SQL_DATA_TYPE     VARCHAR   type code as expected in the SQL CLI SQLDA
     * SQL_DATETIME_SUB  INTEGER   the SQL CLI subtype for DATETIME types
     * CHAR_OCTET_LENGTH INTEGER   for char types, max # of bytes in column
     * ORDINAL_POSITION  INTEGER   1-based index of column in table
     * IS_NULLABLE       VARCHAR   is column nullable? ("YES"|"NO"|""}
     * SCOPE_CATLOG      VARCHAR   catalog of REF attribute scope table
     * SCOPE_SCHEMA      VARCHAR   schema of REF attribute scope table
     * SCOPE_TABLE       VARCHAR   name of REF attribute scope table