Bureaucrats, editor, reviewer, Administrators
13,550
edits
Changes
Jump to navigation
Jump to search
''DraftAfter 15 years of continuous development, yet to be finalized''the first double-digit version of BaseX sees the light of day.
--------We have taken the version jump as an opportunity to perform some major refactorings of BaseX, both under the hood and on API and XQuery level. Before migrating your projects to the new version, some adjustments may be required, so please read this article carefully. =Prerequisites=
After 15 years of continuous development, BaseX 10 requires Java 11 or later to run. Databases created with the first double-digit new version of are backward compatible and can still be opened with BaseX is about to see the light of day soon9.
We have taken the version jump as an opportunity to perform some major refactorings of BaseX, both under the hood and on API and XQuery level. Before migrating your projects to the new version, some adjustments may be required, so please read this article carefully.=Migrating Applications=
=Prerequisites=The following modifications might be relevant when migrating existing applications:
BaseX 10 requires Java 11 or later * The default ports for web applications have been changed from 8984/8985 to run8080/8081. Databases created with BaseX 10 are backward compatible and * The default admin password has been removed. The {{Code|admin}} user can still only be opened used if a password has been assigned, e.g., via the {{Command|PASSWORD}} command.* The conventions for functions in [[Clients]] in other programming languages were revised.* The <code>IGNOREHOSTNAME</code> option was dropped and merged with BaseX 9{{Option|IGNORECERT}}.
With BaseX 10, all All whitespaces are now preserved when importing XML resources, unless whitespace stripping is enabled.
Several The compilation has been split up into multiple steps to improve locking. So far, several internal steps are were already performed when executing a query is executed (see [[XQuery Optimizations#Introduction|XQuery Optimizations]] for more details):
1. # The query is parsed, i.e., the original query string is transformed to an executable tree representation.2. # External values that are passed on by APIs are bound to variables and the query context. External values can be names of databases, or contribute to a name that will be assembled later on be constructed in the query.3. # The query is compiled and evaluated.
With BaseX 10, The compilation has been split into phase now comprises two separate steps:
The Functions of all modules, excluding the [[File Module]], now consistently resolve relative URI references against the static base URI, and not the current working directory. Various modules and functions have been revised, added, renamed or removed: {| class="wikitable"|-! Description! BaseX 10! BaseX 9|-| Retrieve XML resources| {{Function|Database|db:get}}| {{Code|db:open}}|-| Retrieve nodes with specified pre values| {{Function|Database|db:get-pre}}| {{Code|db:open-pre}}|-| Retrieve nodes with specified IDs| {{Function|Database|db:get-id}}| {{Code|db:open-id}}|-| Retrieve binary resources| {{Function|Database|db:get-binary}}| {{Code|db:retrieve}}|-| Retrieve value resources| {{Function|Database|db:get-value}}| ''new''|-| Add or replace resource| {{Function|Database|db:put}}, arguments swapped!| {{Code|db:replace}}|-| Add or replace binary resource| {{Function|Database|db:put-binary}}, arguments swapped!| {{Code|db:store}}|-| Add or replace value resource| {{Function|Database|db:put-value}}| ''new ''|-| Get resource type| {{Function|Database|db:type}}| {{Code|db:is-raw}}, {{Code|db:is-xml}}|-| Fetch XML document| {{Function|Fetch|fetch:doc}}| {{Code|fetch:xml}}|-| Convert binary data to XML| {{Function|Fetch|fetch:binary-doc}}| {{Code|fetch:xml-binary}}|-| Module: Process Geo data| ''removed''| Geo Module|-| XQuery jobs| [[Store Job Module]] provides | Jobs Module|-| Return variable bindings of a persistent mainjob| {{Function|Job|job:bindings}}| ''new''|-| Return variable bindings of a job| {{Function|Job|job:remove}}| {{Code|jobs:stop}}|-| Module: Main-memory key-value store for speeding up operations on frequently accessed data.| [[Store Module]]| ''new''|-| Module: String computations| [[String Module]]| Strings Module|-| Format string| {{Function|String|string:format}}| {{Code|out:format}}|-| Return control characters| {{Function|String|string:cr}}, {{Function|String|string:nl}}, {{Function|String|string:tab}}| {{Code|out:cr}}, {{Code|out:nl}}, {{Code|out:tab}}|-| Module: Process ZIP files| ''removed''| ZIP Module|}
Some existing query modules have been revised:=Commands=
* [[Database Module]]:** Added: {{Function|Database|db:put}}, {{Function|Database|db:get}}.** db:replace → {{Function|Database|db:update}}: Second and third arguments The following commands have been swapped.** db:store → {{Function|Database|db:put-binary}}: Second and third arguments have been swapped.** db:retrieve → {{Function|Database|db:get-binary}}** db:is-raw/db:is-xml → {{Function|Database|db:type}}* [[Fetch Module]]:** fetch:xml → {{Function|Database|fetch:doc}}** fetch:xml-binary → {{Function|Database|fetchrevised:binary-doc}}* The Jobs Module has been renamed to [[Job Module]].* The Strings Module has been renamed to [[String Module]].* The deprecated ZIP Module has been removed.
Functions of all modules, excluding the [[File Module]], now consistently resolve relative URI references against the static base URI, {| class="wikitable"|-! Description! BaseX 10! BaseX 9|-| List directories and not the resources.| {{Command|DIR}}| ''new''|-| Retrieve single XML document| {{Command|GET}}| ''new''|-| Retrieve binary resource| {{Command|BINARY GET}}| {{Code|RETRIEVE}}|-| Add or replace resources| {{Command|PUT}}| {{Code|REPLACE}}|-| Store binary resource| {{Command|BINARY PUT}}| {{Code|STORE}}|-| Returns current working directory.option values| {{Command|SHOW OPTIONS}}| {{Code|GET}}|-| Lists jobs| ''removed''| {{Command|JOBS LIST}}|-| Returns a job result| ''removed''| {{Command|JOBS RESULT}}|-| Stops a job| ''removed''| {{Command|JOBS STOP}}|}
<syntaxhighlight lang="xquery">Graphical User Interface= -DjavaxThe graphical user interface of BaseX has been revised and made more consistent.xml.catalog.resolve=continueQ{javaThe icons were replaced by scalable ones, building upon the [https:System}setProperty('javax//openjdk.xmlorg/jeps/263 HiDPI graphics support for Windows and Linux].catalog.resolve', 'continue')</syntaxhighlight>
→HTTP Requests
=Storage=
==Whitespaces==
The notorious {{Code|CHOP}} option was removed to prevent conflicting behavior caused by earlier installations. It was replaced by a new {{CodeOption|STRIPWS}} option, which defaults to {{Code|false}}. In addition, the new default of the [[Serialization|serialization parameter]] {{Code|indent}} is {{Code|no}}.
Please be warned that the new default can throw off existing applications. If you want to restore the old behavior, you should assign the following values in your [[Configuration|.basex configuration file]], or the {{Code|web.xml}} file of your [[Web Application]]:
<syntaxhighlight lang="xquery">
STRIPWS: true
SERIALIZER: indent=noyes
</syntaxhighlight>
In the GUI editor, a [[Shortcuts#Editor Shortcuts|shortcut]] and an icon were added to switch result indentation on and off.
In addition, databases may considerably increase in size, as whitespaces used for indenting an XML document will be interpreted and stored as additional text nodes. If your XML resources are structured and have no [[Full-Text#Mixed Content|mixed content]], it is advisable to enable whitespaces stripping when importing them to a database.
==Value Resources==
In addition to XML and binary resources, a third resource type has been added: XQuery values (atomic items and nodes, sequences, maps, arrays) can now be stored in databases as well. The {{Function|Database|db:put-value}} and {{Function|Database|db:get-value}} can be used to store to and retrieve values.
The new feature can e.g. be used to store maps in a database:
<syntaxhighlight lang="xquery">
db:put-value(
'factbook',
map:merge(
for $country in db:openget('factbook')//country
return map:entry($country/@name, $country//city/name ! string())
),
<syntaxhighlight lang="xquery">
let $cities := db:get-value('factbook', 'cities')
for $country in ('Japan', 'Indonesia', 'Malaysia')
return $country || ': ' || string-join($cities?($country), ', ')
==Backups==
The [[Commands#Backups|Backup Commands]] and [[Database_Module#Backups|Backup Functions]] were enhanced to back up general data: [[User Management|registered users]], [[Jobs Job Module#Services|scheduled services]], [[Store Module|key-value stores]]. =Applications= The default ports for web applications have been changed from 8984/8985 to 8080/8081. If a new application of BaseX is deployed, the {{Code|admin}} user can only be used after a custom password has been assigned, e.g., via the {{Command|PASSWORD}} command. The <code>IGNOREHOSTNAME</code> option was dropped and merged with {{Option|IGNORECERT}}. =Graphical User Interface= The graphical user interface of BaseX has been revised and made more consistent. The icons were replaced by scalable ones, building upon the [https://openjdk.org/jeps/263 HiDPI graphics support for Windows and Linux].
=XQuery=
==Compilation==
The [[Transaction_Management|transaction manager]] gathers the names of the databases that will be accessed by a query. If it is not possible to uniquely identify all databases that may be opened by the query, global locking will be applied, and all databases will be locked. Detection can fail if the names of databases depend on external input. It can also fail if a query is too complex to associate character strings with database operations.
# ''Compilation'' of logical, context-independent (static) operations. External values are bound to the query, and deterministic code is rewritten, simplified and pre-evaluated.# ''Optimization'' of physical, context-based (dynamic) operations. Addressed databases Databases are opened and checked for available indexes; current date/time is retrieved. The resulting code is further rewritten and optimized.
Lock detection will be performed after the first step, and the code resulting from this step offers much more insight into which specific databases need to be locked. As a result, local locks can be applied to many more queries than before, and many queries can now run in parallel. An example:
<syntaxhighlight lang="xquery">
declare variable $n external;
db:openget('names-' || $n)
</syntaxhighlight>
After the query has been parsed, a user-specific value (e.g., {{Code|123}}) will be bound to {{Code|$n}}. The variable will be inlined by the compiler, and the argument of {{CodeFunction||db:openget}} will be pre-evaluated to {{Code|names123}}. It is then easy for the lock detector to collect the name of the database that needs to read-locked before the query is eventually executed.
Another positive side effect of two-step compilation is that productive environments get faster in general: Queries can be compiled in parallel, and it’s only the optimization and evaluation of a query that may need to be delayed by locking.
==Main-Memory Updates==
XQuery Updates Update provides constructs to [[XQuery Update#Main-Memory Updates|update XML nodes in main memory]]. The data structures for in-memory representations of XML resources have been revised, such that updates can be performed orders of magnitudes faster than before. With BaseX 9.x, the following query runs for 6-7 several minutes, whereas it can now be computed in 3 a few seconds:
<syntaxhighlight lang="xquery">
}
</syntaxhighlight>
==Key-Value Store==
A new [[Store Module]] provides functions to organize values in a persistent main-memory key-value store. The store allows you to speed up access to frequently accessed data.
; Store data:
<syntaxhighlight lang="xquery">
let $email := map:merge(
for $address in db:get('addressbook')//address
return map:entry($address/name, $address/email)
)
return store:put('emails', $email)
</syntaxhighlight>
; Retrieve data:
<syntaxhighlight lang="xquery">
let $name := 'Richard David James'
return store:get('email')($name)
</syntaxhighlight>
The store is persistent: Its contents are written to disk if BaseX is shut down, and retrieved again after a restart.
==Modules==
=HTTP Requests=
HTTP requests in BaseX take advantage of are now based on the new [https://openjdk.org/groups/net/httpclient/intro.html Java HTTP Client]. This client provides a better overall performance, uses internal connection pools and follows redirects across different protocols (http, https).
HTTP operations are, among others, performed by:
=Catalogs=
From early on, catalog resolvers had been neglected both in BaseX and Java. This has changed: The new [https://docs.oracle.com/en/java/javase/11/core/xml-catalog-api1.html XML Catalog API] from Java is now universally used to resolve references to external resources. As an alternative, Norman Walsh’s [https://xmlresolver.org/ Enhanced XML Resolver] will be used is utilized if it is found in the classpath.
The option for supplying the XML catalog was renamed from <code>CATFILE</code> to {{Option|CATALOG}}. See [[Catalog Resolver]] for more details.
=[[REST]]=
Results in the {{Code|rest}} namespace are now returned unprefixedwithout prefix:
<syntaxhighlight lang="xml">
<rest:databases xmlns:rest="http://basex.org/rest"/>
<!-- before now -->
<databases xmlns="http://basex.org/rest"/>
</syntaxhighlight>
When listing the resources of a database, {{Code|dir}} elements are returned for resources that are located in subdirectories. See [[REST]] for more details.
