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--- tutorials:basic-to-advanced-xl-queries [2024/12/04 14:31] – tim2
+++ tutorials:basic-to-advanced-xl-queries [2025/01/10 11:14] (current) – gaetan
@@ Line 1: / Line 1: @@
 ====== From simple to advanced XL queries ======
+This tutorial is more of a quiz than a tutorial, for the different type of queries a graph and a set of quests are provided.
+For each quest, the answer and an explanation is provided. Yet it is important to mention that there can be several solutions, for most of this problems.
+===== Relational queries =====
@@ Line 15: / Line 21: @@
 </code>
-{{ :tutorials:graph_quest_path.png?800 |}}
+|{{ :tutorials:graph_quest_path.png?800 |}}|
+| The graph created by the code above |
-===== Path queries =====
 **0. Get all nodes**
@@ Line 24: / Line 29: @@
 <hidden answer>
+__In a Context:__
-__In a Context:__
 ''%%(*Node*)%%''
 __In a Query:__
 ''%% Node ==> %%''
+__Why:__
+The query system in XL works based on the concept of object orientation from java, therefore a Query also selects all Objects, that extend the class used in the pattern. And since all Nodes in the graph extends the class Node...
 </hidden>
@@ Line 39: / Line 47: @@
 <hidden answer>
+__In a Context:__
 ''%%((*A*))%%''
+__In a Query:__
+''%% A ==> %%''
 </hidden>
@@ Line 50: / Line 66: @@
 ''%%((*Node > B*))%%''
+__In a Query:__
+''%% (*Node > *) B ==> ;%%''
 __Selected Nodes:__
@@ Line 57: / Line 78: @@
 Model.B[id=39]
 </code>
+__Why:__
+The ''>'' arrow describes a successor connection and since Node addresses all Objects in the graph this query addresses all B's that are linked by an successor. For the Query, the use of the context syntax (''%%(*...*)%%'' is necessary to clarify that this part of the pattern is not suppose to be replaced.
 </hidden>
@@ Line 67: / Line 93: @@
 ''%%((*Node +> B*))%%''
+__In a Query:__
+''%% (*Node +> *) B ==> ;%%''
 __Selected Nodes:__
@@ Line 75: / Line 107: @@
 </code>
+__Why:__
+The same as above only with the ''+>'' edge, which represents a branch
 </hidden>
@@ Line 85: / Line 123: @@
 ''%%((*A -->A*))%%''
+__In a Query:__
+''%% (*A --> *) A ==> ;%%''
 __Selected Nodes:__
@@ Line 92: / Line 135: @@
 Model.A[id=38]
 </code>
+__Why:__
+First of all in this case we know what type of parent we are looking for so the first Node is an A but we do not care about the edge and therefore we can use the ''%%-->%%'' term in the pattern which means all edges are possible.
 </hidden>
@@ Line 101: / Line 149: @@
 ''%%((*A +>A*))%%''
+__In a Query:__
+''%% (*A +> *) A ==> ;%%''
 __Selected Nodes:__
@@ Line 108: / Line 162: @@
 </code>
+__Why:__
+Same as above but only for branch edge.
 </hidden>
@@ Line 114: / Line 172: @@
 <hidden answer>
 __In a Context:__
 ''%% (*C (-->)* A*))%%''
+__In a Query:__
+''%% (*C (-->)* *) A ==> ;%%''
 __Selected Nodes:__
@@ Line 125: / Line 190: @@
 Model.A[id=40]
 </code>
+__Why:__
+Now we start at a C because we know at some point above our A there is suppose to be a C, moreover we know that the type of edge does not matter so we can use ''%%-->%%''. Finally we do not only look for the direct connection but for a range of connections this can be done by ''%%()*%%''.
 </hidden>
@@ Line 131: / Line 201: @@
 <hidden answer>
 __In a Context:__
 ''%% (*B (-->)+ B*))%%''
+__In a Query:__
+''%% (*B (-->)+ *) B ==> ;%%''
 __Selected Nodes:__
@@ Line 144: / Line 221: @@
 </code>
+__Why:__
+This is similar to the one above only that we have to make sure that the first B and the second B are not the same Node, To do so we use the (-->)+ pattern, which test any range of connections as well but with at least one edge.
 </hidden>
@@ Line 155: / Line 235: @@
 ''%% (*B --> C --> D*))%%''
+__In a Query:__
+''%% (*B --> C -->*) D ==> ;%%''
 __Selected Nodes:__
@@ Line 161: / Line 247: @@
 Model.D[id=41]
 </code>
+__Why:__
+This follows the same concepts as before only with more than two nodes, if you want you can add as many as you want in a row like this.
 </hidden>
@@ Line 170: / Line 260: @@
 ''%%((*Node +> > +> Node*))%%''
+__In a Query:__
+''%% (*Node +> > +>*) D ==> ;%%''
 __Selected Nodes:__
@@ Line 178: / Line 274: @@
 </code>
+__Why:__
+If you don't care about the type of nodes but only the edges you can just skip the nodes in between. Only the first and the last place have to be a Node.
 </hidden>
@@ Line 183: / Line 282: @@
 **10. Get The B that is a decomposition child of another B, the successor of an C and has a D as a decomposition child.**
 <hidden answer>
 __In a Context:__
 ''%%((*B /> b:B, C > b,D</b*))%%''
+__In a Query:__
+''%%(*B />*)b:B (*< C*),(*D </b*) ==>;%%''
 __Selected Nodes:__
@@ Line 192: / Line 296: @@
 Model.B[id=33]
 </code>
+__Why:__
+  - If you want to combine several conditions in a query you can concatenate them using the comma.
+  - The '/>' edge describes a decomposition edge.
+  - The differences in the two queries are only to highlight the different possibilities.
 </hidden>
@@ Line 202: / Line 312: @@
 ''%%((*a:A,(empty((*a --> Node*)))*))%%''
+__In a Query:__
+''%% a:A,(empty((*a --> Node*))) ==>; %%''
 __Selected Nodes:__
@@ Line 209: / Line 324: @@
 Model.A[id=40]
 </code>
+Besides the pattern of edges and nodes, it is also possible to add concatenate boolean conditions, if they are added in brackets (). In this case the boolean condition is actually the [[:groimp-platform:xl-builtin-methods|XL builtin method]] empty, which returns true if no the query inside does not find any match.
 </hidden>
+**12. Get all the first B's after the A's**
+<hidden answer>
+__In a Context:__
+''%%((* A (-->)+ : (B) *))%%''
+''%%((* A -minDescendants-> B *))%%''
+</hidden>
+===== OOP Queries =====