Edit 3: There is a 2.0 version of sdelete and sdelete64. They appear to be buggy when zeroing. It will appear to be stuck at 100% for extremely long times. Some people have reported 10 - 40 times longer. The older version 1.61 does not have this issue. See -US/2ffb2539-34ba-4378-aa8a-941d243f117e/sdelete-hangs-at-100?forum=miscutils
The first lets you use iCloud to offload files, photos and text messages. You can move all the files stored on your desktop and Documents folder from your Mac's drive to iCloud. And you can store full-resolution photos in iCloud and keep what Apple calls "optimized" versions on your Mac that take up much less space.
Therefore, repeated deletions and downloads result in inconsistent file storage, which is disk fragmentation. Because the file storage location is inconsistent, the reading time of the disk becomes longer, and the computer becomes slower when it is running. So, the ultimate goal of defragmentation is to reorganize the scattered files together continuously to improve the performance of the computer.
Several words are reserved by the standard and cannot be used as table or column names. For example, the word POSITION is reserved as it is a function defined by the Standards with a similar role as String.indexOf() in Java. HSQLDB does not currently prevent you from using a reserved word if it does not support its use or can distinguish it. For example BEGIN is a reserved words that is not currently supported by HSQLDB and is allowed as a table or column name. You should avoid the use of such words as future versions of HSQLDB are likely to support the words and will reject your table definitions or queries. The full list of SQL reserved words is in the source of the org.hsqldb.Token class.
Previous versions of HSQLDB featured poor handling of arithmetic operations. For example, it was not possible to insert 10/2.5 into any DOUBLE or DECIMAL column. Since 1.7.0, full operations are possible with the following rules:
In recent versions leading to 1.8.0 many enhancements were made for better SQL support. These are listed in the SQL Syntax chapter, in ../changelog_1_8_0.txt and ../changelog_1_7_2.txt. Functions and expressions such as POSITION(), SUBSTRING(), NULLIF(), COALESCE(), CASE ... WHEN .. ELSE, ANY, ALL etc. are among them. Other enhancements may not be very obvious in the documentation but can result in changes of behaviour from previous versions. Most significant among these are handling of NULL values in joins (null columns are no longer joined) and OUTER joins (the results are now correct). You should test your applications with the new version to ensure they do not rely on past incorrect behaviour of the engine. The engine will continue to evolve in future versions towards full SQL standard support, so it is best not to rely on any non-standard feature of the current version.
If you want an rpm, you should still find out the current version of HSQLDB as described in the previous paragraph. Then click "hsqldb" in the "free section" of and see if they have the current HSQLDB version built yet. Hopefully, the JPackage folk will document what JVM versions their rpm will support (currently they document this neither on their site nor within the package itself). (I really can't document how to download from a site that is totally beyond my control).
To upgrade from older version database files (1.7.1 and older) that contain CACHED tables, use the SCRIPT procedure below. In all versions of HSQLDB and Hypersonic 1.43, the SCRIPT 'filename' command (used as an SQL query) allows you to save a full record of your database, including database object definitions and data, to a file of your choice. You can export a script file using the old version of the database engine and open the script as a database with 1.8.0. 2b1af7f3a8