types.java

hsql是很有名的嵌入式数据库

        switch (type) {

            case Types.DECIMAL :
            case Types.NUMERIC :
                return true;

            default :
                return false;
        }
    }

    public static boolean isNumberType(int type) {

        switch (type) {

            case BIGINT :
            case DECIMAL :
            case DOUBLE :
            case FLOAT :
            case INTEGER :
            case NUMERIC :
            case REAL :
            case SMALLINT :
            case TINYINT :
                return true;

            default :
                return false;
        }
    }

    public static boolean isCharacterType(int type) {

        switch (type) {

            case CHAR :
            case CLOB :
            case LONGVARCHAR :
            case VARCHAR :
            case VARCHAR_IGNORECASE :
                return true;

            default :
                return false;
        }
    }

    public static String getTypeName(int type) {

        switch (type) {

            case Types.ARRAY :
                return "ARRAY";

            case Types.BIGINT :
                return "BIGINT";

            case Types.BINARY :
                return "BINARY";

            case Types.BLOB :
                return "BLOB";

            case Types.BOOLEAN :
                return "BOOLEAN";

            case Types.CHAR :
                return "CHAR";

            case Types.CLOB :
                return "CLOB";

            case Types.DATALINK :
                return "DATALINK";

            case Types.DATE :
                return "DATE";

            case Types.DECIMAL :
                return "DECIMAL";

            case Types.DISTINCT :
                return "DISTINCT";

            case Types.DOUBLE :
                return "DOUBLE";

            case Types.FLOAT :
                return "FLOAT";

            case Types.INTEGER :
                return "INTEGER";

            case Types.JAVA_OBJECT :
                return "JAVA_OBJECT";

            case Types.LONGVARBINARY :
                return "LONGVARBINARY";

            case Types.LONGVARCHAR :
                return "LONGVARCHAR";

            case Types.NULL :
                return "NULL";

            case Types.NUMERIC :
                return "NUMERIC";

            case Types.OTHER :
                return "OTHER";

            case Types.REAL :
                return "REAL";

            case Types.REF :
                return "REF";

            case Types.SMALLINT :
                return "SMALLINT";

            case Types.STRUCT :
                return "STUCT";

            case Types.TIME :
                return "TIME";

            case Types.TIMESTAMP :
                return "TIMESTAMP";

            case Types.TINYINT :
                return "TINYINT";

            case Types.VARBINARY :
                return "VARBINARY";

            case Types.VARCHAR :
                return "VARCHAR";

            case Types.VARCHAR_IGNORECASE :
                return "VARCHAR_IGNORECASE";

            case Types.XML :
                return "XML";

            default :
                return null;
        }
    }

    /**
     * A reasonable/customizable number to avoid the shortcomings/defects
     * associated with doing a dynamic scan of results to determine
     * the value.  In practice, it turns out that single query yielding
     * widely varying values for display size of CHAR and VARCHAR columns
     * on repeated execution results in patently poor usability, as some fairly
     * high-profile, otherwise "enterprise-quality" RAD tools depend on
     * on the first value returned to lay out forms and limit the size of
     * single line edit controls, set corresponding local datastore storage
     * sizes, etc. In practice, It also turns out that many tools (due to
     * the original lack of PreparedStatement.getMetaData() in JDK 1.1) emulate
     * a SQL_DESCRIBE by executing a query hopefully guaranteed to return no
     * or very few rows for example: select ... from ... where 1=0.
     * Using the dynamic scan of 1.7.2 RC5 and previous, therefore, the
     * minimum display size value (1) was often being generated during
     * a tool's describe phase.  Upon subsequent "real" retrievals, some
     * tools complain that CHAR and VARCHAR result values exceeded the
     * originally reported display size and refused to fetch further values.
     */
    public static final int MAX_CHAR_OR_VARCHAR_DISPLAY_SIZE =
        MAX_CHAR_OR_VARCHAR_DISPLAY_SIZE();

    // So that the variable can be both public static final and
    // customizable through system properties if required.
    //
    // 32766 (0x7ffe) seems to be a magic number over which several
    // rather high-profile RAD tools start to have problems
    // regarding layout and allocation stress.  It is gently
    // recommended that LONGVARCHAR be used for larger values in RAD
    // tool layout & presentation use cases until such time as we provide
    // true BLOB support (at which point, LONGVARCHAR will most likely become
    // an alias for CLOB).
    //
    // Most GUI tools seem to handle LONGVARCHAR gracefully by:
    //
    // 1.) refusing to directly display such columns in graphical query results
    // 2.) providing other means to retrieve and display such values
    private static int MAX_CHAR_OR_VARCHAR_DISPLAY_SIZE() {

        try {
            return Integer.getInteger(
                "hsqldb.max_char_or_varchar_display_size", 32766).intValue();
        } catch (SecurityException e) {
            return 32766;
        }
    }

    public static int getMaxDisplaySize(int type) {

        switch (type) {

            case Types.BINARY :
            case Types.LONGVARBINARY :
            case Types.LONGVARCHAR :
            case Types.OTHER :
            case Types.VARBINARY :
            case Types.XML :
                return Integer.MAX_VALUE;    // max string length

            case Types.CHAR :
            case Types.VARCHAR :
                return MAX_CHAR_OR_VARCHAR_DISPLAY_SIZE;

            case Types.BIGINT :              // PowerBuilder barfs, wants 19

                // ...not our problem, tho,
                // according to JDBC
                return 20;                   // precision + "-".length();

            case Types.BOOLEAN :
                return 5;                    // Math.max("true".length(),"false".length);

            case Types.DATALINK :
                return 20004;                // same as precision

            case Types.DECIMAL :
            case Types.NUMERIC :
                return 646456995;            // precision + "-.".length()

            case Types.DATE :
                return 10;                   // same as precision

            case Types.INTEGER :
                return 11;                   // precision + "-".length();

            case Types.FLOAT :
            case Types.REAL :
            case Types.DOUBLE :
                return 23;                   // String.valueOf(-Double.MAX_VALUE).length();

            case Types.TIME :
                return 8;                    // same as precision

            case Types.SMALLINT :
                return 6;                    // precision + "-".length();

            case Types.TIMESTAMP :
                return 29;                   // same as precision

            case Types.TINYINT :
                return 4;                    // precision + "-".length();

            default :
                return 0;                    // unknown
        }
    }

    public static boolean isSearchable(int type) {

        switch (type) {

            case Types.ARRAY :
            case Types.BLOB :
            case Types.CLOB :
            case Types.JAVA_OBJECT :
            case Types.STRUCT :
            case Types.OTHER :
                return false;

            default :
                return true;
        }
    }

    public static Boolean isCaseSensitive(int type) {

        switch (type) {

            case Types.ARRAY :
            case Types.BLOB :
            case Types.CLOB :
            case Types.DISTINCT :
            case Types.JAVA_OBJECT :
            case Types.NULL :
            case Types.REF :
            case Types.STRUCT :
                return null;

            case Types.CHAR :
            case Types.DATALINK :
            case Types.LONGVARCHAR :
            case Types.OTHER :
            case Types.XML :
                return Boolean.TRUE;

            case Types.VARCHAR_IGNORECASE :
            default :
                return Boolean.FALSE;
        }
    }

    public static Boolean isUnsignedAttribute(int type) {

        switch (type) {

            case Types.BIGINT :
            case Types.DECIMAL :
            case Types.DOUBLE :
            case Types.FLOAT :
            case Types.INTEGER :
            case Types.NUMERIC :
            case Types.REAL :
            case Types.SMALLINT :
            case Types.TINYINT :
                return Boolean.FALSE;

            default :
                return null;
        }
    }

    public static int getPrecision(int type) {

        switch (type) {

            case Types.BINARY :
            case Types.CHAR :
            case Types.LONGVARBINARY :
            case Types.LONGVARCHAR :
            case Types.OTHER :
            case Types.VARBINARY :
            case Types.VARCHAR :
            case Types.XML :
                return Integer.MAX_VALUE;

            case Types.BIGINT :
                return 19;

            case Types.BOOLEAN :
                return 1;

            case Types.DATALINK :

                // from SQL CLI spec.  TODO:  Interpretation?
                return 20004;

            case Types.DECIMAL :
            case Types.NUMERIC :

// Integer.MAX_VALUE bit 2's complement number:
// (Integer.MAX_VALUE-1) / ((ln(10)/ln(2)) bits per decimal digit)
// See:  java.math.BigInteger
// - the other alternative is that we could report the numprecradix as 2 and
// report Integer.MAX_VALUE here
                return 646456993;

            case Types.DATE :
            case Types.INTEGER :
                return 10;

            case Types.FLOAT :
            case Types.REAL :
            case Types.DOUBLE :
                return 17;

            case Types.TIME :
                return 8;

            case Types.SMALLINT :
                return 5;

            case Types.TIMESTAMP :
                return 29;

            case Types.TINYINT :
                return 3;

            default :
                return 0;
        }
    }

    public static String getColStClsName(int type) {

        switch (type) {

            case Types.BIGINT :
                return "java.lang.Long";

            case Types.BINARY :
            case Types.LONGVARBINARY :
            case Types.VARBINARY :

                // but wrapped by org.hsqldb.Binary
                return "[B";

            case Types.OTHER :

                // but wrapped by org.hsqldb.JavaObject
                return "java.lang.Object";

            case Types.BOOLEAN :
                return "java.lang.Boolean";

            case Types.CHAR :
            case Types.LONGVARCHAR :
            case Types.VARCHAR :
            case Types.XML :    //?
                return "java.lang.String";

            case Types.DATALINK :
                return "java.net.URL";

            case Types.DATE :
                return DateClassName;

            case Types.DECIMAL :
            case Types.NUMERIC :
                return DecimalClassName;

            case Types.DOUBLE :
            case Types.FLOAT :
            case Types.REAL :
                return "java.lang.Double";

            case Types.INTEGER :
            case Types.SMALLINT :
            case Types.TINYINT :
                return "java.lang.Integer";

            case Types.TIME :
                return TimeClassName;

            case Types.TIMESTAMP :
                return TimestampClassName;

            default :
                return null;
        }
    }
}