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3.1. Introduction

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3.3. Implementation

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3.2. RQL syntax

3.2.1. Reserved keywords

The keywords are not case sensitive.

AND, ASC, BEING, DELETE, DESC, DISTINCT, EXISTS, FALSE, GROUPBY,
HAVING, ILIKE, IN, INSERT, LIKE, LIMIT, NOT, NOW, NULL, OFFSET,
OR, ORDERBY, SET, TODAY, TRUE, UNION, WHERE, WITH

3.2.2. Variables and Typing

With RQL, we do not distinguish between entities and attributes. The value of an attribute is considered an entity of a particular type (see below), linked to one (real) entity by a relation called the name of the attribute.

Entities and values to browse and/or select are represented in the query by variables that must be written in capital letters.

There is a special type Any, referring to a non specific type.

We can restrict the possible types for a variable using the special relation is. The possible type(s) for each variable is derived from the schema according to the constraints expressed above and thanks to the relations between each variable.

3.2.2.1. Built-in types

The base types supported are string (between double or single quotes), integers or floats (the separator is ‘.’), dates and boolean. We expect to receive a schema in which types String, Int, Float, Date and Boolean are defined.

  • String (literal: between double or single quotes).
  • Int, Float (separator being’.’).
  • Date, Datetime, Time (literal: string YYYY/MM/DD [hh:mm] or keywords TODAY and NOW).
  • Boolean (keywords TRUE and FALSE).
  • Keyword NULL.

3.2.3. Operators

3.2.3.1. Logical Operators

   AND, OR, NOT, ','

',' is equivalent to 'AND' but with the smallest among the priority
of logical operators (see :ref:`PriorityOperators`).

3.2.3.2. Mathematical Operators

+, -, *, /

3.2.3.3. Comparison operators

=, <, <=, >=, >, ~=, IN, LIKE, ILIKE
  • The operator = is the default operator.

  • The operator LIKE equivalent to ~= can be used with the special character % in a string to indicate that the chain must start or finish by a prefix/suffix:

    Any X WHERE X name ~= 'Th%'
    Any X WHERE X name LIKE '%lt'
  • The operator ILIKE is the case insensitive version of LIKE.

  • The operator IN provides a list of possible values:

    Any X WHERE X name IN ( 'chauvat', 'fayolle', 'di mascio', 'thenault')

3.2.3.4. Operators priority

  1. ‘*’, ‘/’
  2. ‘+’, ‘-‘
  3. ‘not’

4 ‘and’

5 ‘or’

6 ‘,’

3.2.4. Search Query

[ DISTINCT] <entity type> V1 (, V2) * [ GROUPBY V1 (V2) *] [ ORDERBY <orderterms>] [ LIMIT <value>] [ OFFSET <value>] [ WHERE <restriction>] [ WITH V1 (, V2) * BEING (<query>)] [ HAVING <restriction>] [ UNION <query>]
entity type:

Type of selected variables. The special type Any is equivalent to not specify a type.

restriction:
list of conditions to test successively

V1 relation V2 | <static value>

orderterms:

Definition of the selection order: variable or column number followed by sorting method ( ASC, DESC), ASC is the default.

note for grouped queries:
 

For grouped queries (e.g., a clause GROUPBY), all selected variables must be aggregated or grouped.

3.2.4.1. Sorting and groups

  • For grouped queries (e.g. with a GROUPBY clause), all selected variables should be grouped.
  • To group and/or sort by attributes, we can do: “X,L user U, U login L GROUPBY L, X ORDERBY L”
  • If the sorting method (SORT_METHOD) is not specified, then the sorting is ascendant.
  • Aggregate Functions: COUNT, MIN, MAX, AVG, SUM

3.2.4.2. Negation

  • A query such as Document X WHERE NOT X owned_by U means “the documents have no relation owned_by“.
  • But the query Document X WHERE NOT X owned_by U, U login “syt” means “the documents have no relation owned_by with the user syt”. They may have a relation “owned_by” with another user.

3.2.4.3. Identity

You can use the special relation identity in a query to add an identity constraint between two variables. This is equivalent to is in python:

Any A WHERE A comments B, A identity B

return all objects that comment themselves. The relation identity is especially useful when defining the rules for securities with RQLExpressions.

3.2.4.4. Limit / offset

Any P ORDERBY N LIMIT 5 OFFSET 10 WHERE P is Person, P firstname N

3.2.4.5. Function calls

Any UPPER(N) WHERE P firstname N

Functions on string: UPPER, LOWER

3.2.4.6. Exists

Any X ORDERBY PN,N
WHERE X num N, X version_of P, P name PN,
      EXISTS(X in_state S, S name IN ("dev", "ready"))
      OR EXISTS(T tags X, T name "priority")

3.2.4.7. Optional relations (Left outer join)

  • They allow you to select entities related or not to another.

  • You must use the ? behind the variable to specify that the relation toward it is optional:

    • Anomalies of a project attached or not to a version

      Any X, V WHERE X concerns P, P eid 42, X corrected_in V?
    • All cards and the project they document if necessary

      Any C, P WHERE C is Card, P? documented_by C

    Any T,P,V WHERE T is Ticket, T concerns P, T done_in V?

3.2.4.8. Having

Any X GROUPBY X WHERE X knows Y HAVING COUNT(Y) > 10

3.2.4.9. Subqueries

(Any X WHERE X is Person) UNION (Any X WHERE X is Company)


 DISTINCT Any W, REF
    WITH W, REF BEING
        (
          (Any W, REF WHERE W is Workcase, W ref REF,
                             W concerned_by D, D name "Logilab")
           UNION
          (Any W, REF WHERE W is Workcase, W ref REF, '
                            W split_into WP, WP name "WP1")
        )

3.2.4.10. Examples

  • Search for the object of identifier 53

    Any WHERE X
    X eid 53
  • Search material such as comics, owned by syt and available

    Any X WHERE X is Document
    X occurence_of F, F class C, C name 'Comics'
    X owned_by U, U login 'syt'
    X available TRUE
  • Looking for people working for eurocopter interested in training

    Any P WHERE
    P is Person, P work_for S, S name 'Eurocopter'
    P interested_by T, T name 'training'
  • Search note less than 10 days old written by jphc or ocy

    Any N WHERE
    N is Note, N written_on D, D day> (today -10),
    N written_by P, P name 'jphc' or P name 'ocy'
  • Looking for people interested in training or living in Paris

    Any P WHERE
    P is Person, (P interested_by T, T name 'training') OR
    (P city 'Paris')
  • The name and surname of all people

    Any N, P WHERE
    X is Person, X name N, X first_name P

    Note that the selection of several entities generally force the use of “Any” because the type specification applies otherwise to all the selected variables. We could write here

    String N, P WHERE
    X is Person, X name N, X first_name P

    Note: You can not specify several types with * ... where X is FirstType or X is SecondType*. To specify several types explicitly, you have to do

    Any X where X is in (FirstType, SecondType)

3.2.5. Insertion query

INSERT <entity type> V1 (, <entity type> V2) * : <assignments> [ WHERE <restriction>]
assignments:list of relations to assign in the form V1 relationship V2 | <static value>

The restriction can define variables used in assignments.

Caution, if a restriction is specified, the insertion is done for each line result returned by the restriction.

  • Insert a new person named ‘foo’

    INSERT Person X: X name 'foo'
  • Insert a new person named ‘foo’, another called ‘nice’ and a ‘friend’ relation between them

    INSERT Person X, Person Y: X name 'foo', Y name 'nice', X friend Y
  • Insert a new person named ‘foo’ and a ‘friend’ relation with an existing person called ‘nice’

    INSERT Person X: X name 'foo', X friend  Y WHERE name 'nice'

3.2.6. Update and relation creation queries

SET <assignements> [ WHERE <restriction>]

Caution, if a restriction is specified, the update is done for each result line returned by the restriction.

  • Renaming of the person named ‘foo’ to ‘bar’ with the first name changed

    SET X name 'bar', X first_name 'original' WHERE X is Person, X name 'foo'
  • Insert a relation of type ‘know’ between objects linked by the relation of type ‘friend’

    SET X know Y  WHERE X friend Y

3.2.7. Deletion query

DELETE (<entity type> V) | (V1 relation v2 ),... [ WHERE <restriction>]

Caution, if a restriction is specified, the deletion is made for each line result returned by the restriction.

  • Deletion of the person named ‘foo’

    DELETE Person X WHERE X name 'foo'
  • Removal of all relations of type ‘friend’ from the person named ‘foo’

    DELETE X friend Y WHERE X is Person, X name 'foo'

3.2.8. Virtual RQL relations

Those relations may only be used in RQL query and are not actual attributes of your entities.

  • has_text: relation to use to query the full text index (only for entities having fulltextindexed attributes).
  • identity: relation to use to tell that a RQL variable should be the same as another (but you’ve to use two different rql variables for querying purpose)