As (query directive) - Revision history

Olli: /* Exmaples */

2009-08-20T09:32:58Z

‎Exmaples

Olli: /* Exmaples */

2009-08-20T09:27:03Z

‎Exmaples

Olli at 08:46, 20 August 2009

2009-08-20T08:46:07Z

Olli at 07:30, 20 August 2009

2009-08-20T07:30:28Z

New page

== Description ==

Changes the role name of the active column or the specified column.

== Constructor ==

As(String newRole) - Change the role name of the active column.

As(String original, String newRole) - Change the role name of the specified column.

== Notes ==

Generally you have to feed rows to As directive from some other directive through a From directive. All this is best done using the as method present in every directive. Calling A.as("role") will change the active column role name of the results of A. This will resolve to new As("role").from(A) which resolves to new From(new As("role"),A)'. The as method can also be given two parameters corresponding to the As directive constructor with two parameters.

[[Category:Query directives]]

@@ Line 34: / Line 34: @@
 )
-The ''as'' method call on line 6 changes the role of instances so we can refer to it later. Line 7 uses ''As'' constructor directly. Input to this directive is actually the initial input to the entire query. Thus the ''As'' directive on line 7 changes the actual input topic role name to "#input". Normally the input topic uses the default role and so will get overwritten almost immediately. This is one of few cases where you may need to construct ''As'' directive directly.
+The ''as'' method call on line 6 changes the role of instances so we can refer to it later. Line 7 uses ''As'' constructor directly. Input to this directive is actually the initial input to the entire query. Thus the ''As'' directive on line 7 changes the actual input topic role name to "#input". Normally the input topic uses the default role and so will get overwritten almost immediately. This is one of few cases where you may need to construct ''As'' directive directly. This can also be done using the ''to'' method which is inverse of ''from''.
 [[Category:Query directives]]

← Older revision		Revision as of 09:27, 20 August 2009
Line 23:		Line 23:
	new From(new As("#instance"),new Instances())		new From(new As("#instance"),new Instances())

		+	Below is a slightly more complex example demonstrating both changing active column role with ''as'' and then later referring to them with ''of'' (see also [[Of (query directive) \|Of]] directive).
		+
		+	1 importPackage(org.wandora.query2);
		+	2 new Join(
		+	3 new BaseName().of("#input").as("#inputbn"),
		+	4 new BaseName().of("#instance").as("#instancebn")
		+	5 ).from(
		+	6 new Instances().as("#instance").from(
		+	7 new As("#input"))
		+	8 )
		+
		+	The ''as'' method call on line 6 changes the role of instances so we can refer to it later. Line 7 uses ''As'' constructor directly. Input to this directive is actually the initial input to the entire query. Thus the ''As'' directive on line 7 changes the actual input topic role name to "#input". Normally the input topic uses the default role and so will get overwritten almost immediately. This is one of few cases where you may need to construct ''As'' directive directly.

	[[Category:Query directives]]		[[Category:Query directives]]

@@ Line 11: / Line 11: @@
 == Notes ==
-Generally you have to feed rows to As directive from some other directive through a From directive. All this is best done using the as method present in every directive. Calling A.as("role") will change the active column role name of the results of A. This will resolve to new As("role").from(A) which resolves to new From(new As("role"),A)'. The as method can also be given two parameters corresponding to the As directive constructor with two parameters.
+Generally you have to feed rows to ''As'' directive from some other directive through a ''From'' directive. All this is best done using the ''as'' method present in every directive. Calling ''A.as("role")'' will change the active column role name of the results of A. This will resolve to ''new As("role").from(A)'' which resolves to ''new From(new As("role"),A)''. The ''as'' method can also be given two parameters corresponding to the ''As'' directive constructor with two parameters.
 [[Category:Query directives]]