Dear TCG,
following the standard procedure, please find attached the ADQL
Document proposed for Recommendation, updated following the RFC
comments and interactions during the last interop meeting. The
document can also be found at:
http://www.ivoa.net/internal/IVOA/IvoaVOQL/ADQL-v2.0-20080908.pdf
Placeholders have been allocated at the bottom of the RFC pages at:
http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/ADQLv2RFC
where you should write the approval for the document or otherwise with
eventual comments if any.
Regards,
Pedro Osuna for the VOQL group
Document change log
- New document created with track changes enabled. All additions and
deletions are shown.
As suggested by Pat's on 23 May 2008, we could also accept the
deletions and show the additions only.
- Typos and editorial issues corrected as of RFC comments by Bob Hanish.
- Join description improved as suggested by Jeff's email 'Spec (BNF)
changes parallel to the RFC' on 28 May 2008.
- In Section 2.1.3, paragraph added clarifying the usage of datetime/
timestamp data types through the string
literal construct.
- Following the RFC comments on units, trigonometrical functions
definition
have been improved including required units and legal return and
input values.
- Following the RFC comments, Mathematical and trigonometrical
functions table split
into two to be consistent with BNF.
- Remove Manipulative functions section as CENTROID is now part of the
Geometrical Data Types functions.
- Update list of geometrical reserved keywords to be consistent with
BNF. LONGITUDE and LATITUDE replaced by
COORD1, COORD2. RECTANGLE replaced by BOX.
- Following the RFC comments, new function COORDSYS added to extract
the coordinate system
from a given geometry. Keyword added to the list of keywords on
section 2.4 Geometrical Functions.
- All BNF excerpts under the Geometrical Function section (old Region
section) have been updated to be consistent
with latest BNF.
- Following the RFC comments, subsectioning has been improved to
reduce the section levels. As a result The Functions section has been
split into three: Mathematical Functions, Geometrical Functions and
User Defined Functions. Geometrical Functions section
now covers the Region stuff and has also reduced the section levels
for the sake of readability.
- As agreed among the TEG members it has been explicitly stated that
ADQL uses degrees everywhere in the geometry
constructs and region strings while trig functions, adopted from
SQL, use radians. When cartesian coordinates are
used the restriction is that the vector must be normalized.
- Legal ranges for spherical coordinates have been set to [0,360] and
[-90,90]. In a cartesian coordinate system,
there are no inherent limits but the constrain that vectors should
be normalized. Document now clarifies that
it's up to the service making use of ADQL to define the errors that
should be raised when using values outside
the legal ranges.
- Added text into the introduction stating the ADQL language is not
semantically safe by design (nor SQL) and the
specification defines syntactical correctness only.
- Following the RFC comments, links to STC and STC-S have been added
in the 'References' section and reference
to both within the 'Geometrical Functions' section.
- Broken link for Reference [2] fixed. Now pointing to http://www.ietf.org/rfc/rfc2119.txt
- Coordinate system string literals must be specified by the service.
A list of such literals can be found in
Appendix of STC document.
- Following the RFC comments, BOX defined as of STC replacing
RECTANGLE. Samples of usage provided.
- Improved samples and description for AREA, CENTROID, CIRCLE,
CONTAIN, INTERSECTS, POINT, POLYGON and REGION
functions.
- Following the RFC comments, LATITUDE and LONGITUDE functions have
been replaced by COORD1, COORD2, these being
more generic and not attached to the spherical coordinate.
- New functions COORDSYS to extract a coordinate system from a geometry.
- Define use cases where CONTAINS and INTERSECTS should throw an error
message (to be defined explicitely by the
service making use of ADQL).
- New BNF grammar provided by Jeff with minor corrections (see
differences below).
- Remove SQUARE and replace MODE by MOD on list of ADQL reserved
keywords (section 2.1.2)
BNF change log
- Change in ADQL reserved words list: Added BOX, COORD1, COORD2,
COORDSYS. Deleted LATITUDE, LONGITUDE, MODE
RECTANLE, and SQUARE.
- box construct added.
- centroid syntax updated now using geometry_value_expression instead
of geometry_expression.
- character primary updated to use string_value_function instead of
user_defined_function.
- new constructs string_value_function, string_geometry_function> and
<extract_coordsys>
- SQUARE function taken out to be consistent with spec.
- contains_function replaced by contains.
- coord_lon and coord_lat replaced by coord1, coord2 constructs.
- new constructs coord_value, coordinate1 and coordinate2.
- distance function update now taking twoo coord_value constructs.
- extract_coordsys construct added.
- geometry_expression replaced by geometry_value_function with box,
centroid, circle, point, polygon
and region. geometry_value removed. geometry_value_expression
updated accordingly.
- intersects_function replaced by intersects.
- latitude, longitude constructs taken out.
- new constructs non_predicate_geometry_function,
predicate_geometry_function and numeric_geometry_function added.
- <system_defined_function> changed to <geometry_function>.
numeric_value_function uses <geometry_function>
instead.
- rectangle construct taken out.
- region_function construct taken out (replaced by
predicate_geometry_function)
- Added MOD function as described by the spec.
Pedro Osuna Alcalaya
European Space Agency (ESA)
European Space Astronomy Centre (ESAC)
Science Operations Department (SCI-O)
Science Archives and Computer Support Engineering Unit (SCI-OE)
e-mail: Pedro.Osuna-at-esa.int
Tel + 34 91 813 13 14 Fax: +34 91 813 11 72
European Space Astronomy Centre (ESAC)
P.O. Box 78
E-28691 Villanueva de la Caņada
MADRID - SPAIN
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Received on 2008-09-15Z11:21:01