Hi all,
OrientDB allowed to execute arbitrary script written in Javascript or any
scripting language installed in the JVM. Well, starting from now we created
a minimal SQL engine to allow batch of commands.
Batch of commands are very useful when you have to execute multiple things
at the server side avoiding the network roundtrip for each command.
Example to create a new vertex in a transaction and attach it to an
existent vertex by creating a new edge between them:
*beginlet account = create vertex Account set name = 'Luke'let city =
select from City where name = 'London'let edge = create edge Lives from
$account to $city retry 100 commitreturn $edge*
It's plain OrientDB SQL, but with few news:
- *begin* -> begins a transaction
- *rollback* -> rollbacks an active transaction
- *commit* -> commits an active transaction
- *let <variable> = <command>* -> executes a command and assign it in
the context as . That variable can be used in further commands by prefixing
it with $
- *return* <variable>|<value>|null -> returns a value instead of last
command result (default
Note also the usage of* $account *and* $city* on further SQL commands.
*Java API*
This can be used by Java API with:
database.open("admin", "admin");
String cmd = "begin\n";cmd += "let a = create vertex set script =
true\n";cmd += "let b = select from v limit 1\n";cmd += "let e =
create edge from $a to $b retry 100\n";cmd += "commit\n";cmd +=
"return $e";
OIdentifiable edge = database.command(new OCommandScript("sql", cmd)).execute();
Remember to put one command per line (postfix it with \n).
*HTTP REST API*
And via HTTP REST interface (
https://github.com/orientechnologies/orientdb/issues/2056). Execute a POST
against /batch URL by sending this payload:
{ "transaction" : true,
"operations" : [
{
"type" : "script",
"language" : "sql",
"script" : [ "let account = create vertex Account set name = 'Luke'",
"let city =select from City where name = 'London'",
"create edge Lives from $account to $city retry 100" ]
}
]}
Hope this new feature will simplify your development improving performance.
What about having more complex constructs like IF, FOR, etc? If you need
more complexity, I suggest you to use Javascript as language that already
support all these concepts.
Lvc@
PS: For more information look at issues ->
https://github.com/orientechnologies/orientdb/issues/2176 and
https://github.com/orientechnologies/orientdb/issues/2056
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