VODataService xs vs An extension to the core resource metadata (VOResource) for describing data collections and services. A logical grouping of data which, in general, is composed of one or more accessible datasets. A collection can contain any combination of images, spectra, catalogues, or other data. (A dataset is a collection of digitally-encoded data that is normally accessible as a single unit, e.g., a file.) This type is deprecated. Resource record authors should use vs:CatalogResource instead. This type will be removed from the schema when no resource record using it remains in the registry. Subject the observatory or facility used to collect the data contained or managed by this resource. Subject Subject.Instrument the Instrument used to collect the data contain or managed by a resource. Rights Information about rights held in and over the resource. This should be repeated for all Rights values that apply. The physical or digital manifestation of the information supported by a resource. This should use RFC 2046 media (“MIME”) types for network-retrievable, digital data. Non-RFC 2046 values could be used for media that cannot be retrieved over the network. Extent of the content of the resource over space, time, and frequency. A description of the tables that are part of this collection. Each schema name must be unique within a tableset. The URL that can be used to download the data contained in this data collection. A coverage on a sphere. By default, this refers to the celestial sphere in the ICRS frame. Non-celestial frames are indicated by non-NULL values of the frame attribute. When present, the MOC is written in a non-celestial (e.g., planetary) frame. Note that for celestial coverages, ICRS must be used. VODataService 1.2 does not prescribe a vocabulary for what values are allowed here. As long as no such vocabulary is agreed upon, the frame attribute should not be set. A description of how a resource's contents or behavior maps to the sky, to time, and to frequency space, including coverage and resolution. An STC 1.0 description of the location of the resource's data on the sky, in time, and in frequency space, including resolution. This is deprecated in favour of the separate spatial, temporal, and spectral elements. An ASCII-serialized MOC defining the spatial coverage of the resource. The MOC is to be understood in the ICRS reference frame unless a frame attribute is given. Resources should give the coverage at least to order 6 (a resolution of about one degree). The order should be chosen so as to keep the resulting MOC smaller than a few dozens of kB. If desired, a more precise MOC can be provided on a dedicated endpoint declared in the footprint element. A pair of lower, upper limits of a time interval for which the resource offers data. This is written as for VOTable tabledata (i.e., whitespace-separated C-style floating point literals), as in “47847.2 51370.2”. The limits must be given as MJD. While they are not intended to be precise, they are to be understood in TDB for the solar system barycenter. The total coverage of the resource is the union of all such intervals. A pair of lower, upper limits of a spectral interval for which the resource offers data. This is written as for VOTable tabledata (i.e., whitespace-separated C-style floating point literals). The limits must be given in Joules of particle energies. While the limits are not intended to be precise, they are to be understood for the solar system barycenter. For instance, the Johnson V waveband (480 .. 730 nm) would be specified as “2.72e-19 4.14e-19” A reference to a footprint service for retrieving precise and up-to-date description of coverage. The ivo-id attribute here refers to the standard in which the footprint is given. The only value defined by VODataService at this point is ivo://ivoa.net/std/moc, which indicates that retrieving the footprint URL will return a MOC (any IVOA-approved serialisation is legal). Note that the ivo-id attribute was intended to have a different function in VODataService 1.1. The current meaning is what implementors actually adopted. Coverage.Spectral A name of a messenger that the resource is relevant for (e.g., was used in the measurements). Terms must be taken from the vocabulary at http://www.ivoa.net/rdf/messenger. It is a bit unfortunate that the element is still called waveband when it is now also covers non-electromagnetic messengers. It was deemed that this slight notional sloppiness is preferable to introducing new and deprecating old elements. Coverage.RegionOfRegard A single numeric value representing the angle, given in decimal degrees, by which a positional query against this resource should be “blurred” in order to get an appropriate match. In the case of image repositories, it might refer to a typical field-of-view size, or the primary beam size for radio aperture synthesis data. In the case of object catalogues RoR should normally be the largest of the typical size of the objects, the astrometric errors in the positions, or the resolution of the data. The service URL for a potentially registered service. That is, if an IVOA identifier is also provided, then the service is described in a registry. The URI form of the IVOA identifier for the service describing the capability refered to by this element. The set of tables hosted by a resource. A named description of a group of logically related tables. The name given by the “name” child element must be unique within this TableSet instance. If there is only one schema in this set and/or there is no locally appropriate name to provide, the name can be set to “default”. This aggregation does not need to map to an actual database, catalogue, or schema, though the publisher may choose to aggregate along such designations. Particular service protocols may require stricter patterns. A detailed description of a logically related group of tables. A name for the group of tables. This is used to uniquely identify the group of tables among several groups. If no title is given, this name can be used for display purposes. If there is no appropriate logical name associated with this group, the name should be explicitly set to “default”. A descriptive, human-interpretable name for the group of tables. This is used for display purposes. There is no requirement regarding uniqueness. It is useful when there are multiple schemas in the context (e.g., within a tableset; otherwise, the resource title could be used instead). A free text description of the group of tables that should explain in general how all of the tables in the group are related. An identifier for a concept in a data model that the data in this schema as a whole represent. The form of the utype string depends on the data model; common forms are sequences of dotted identifiers (e.g., in SSA) or URIs (e.g., in RegTAP). A description of one table. If true, the content of the element is an RFC 2046-compliant media time. A resource publishing astronomical data. This resource type should only be used if the resource has no common underlying tabular schema (e.g., an inhomogeneous archive). Use CatalogResource otherwise. Subject The observatory or facility used to collect the data contained or managed by this resource. Subject Subject.Instrument The instrument used to collect the data contain or managed by a resource. Extent of the content of the resource over space, time, and frequency. A service for accessing astronomical data. This resource type should only be used if the service has no common underlying tabular schema (e.g., a storage service) or if it is not explicitly accessible (e.g., an ftp server with images). Use CatalogService otherwise. A service invoked via an HTTP Query (either Get or Post) with a set of arguments consisting of keyword name-value pairs. Note that the URL for help with this service can be put into the service/referenceURL element. The type of HTTP request, either GET or POST. The service may indicate support for both GET and POST by providing 2 queryType elements, one with GET and one with POST. Since the IVOA standard DALI requires standard services to support both GET and POST, this piece of metadata is not useful in the description of standard DAL services and does not need to be given for those. The MIME media type of a document returned in the HTTP response. A description of a input parameter that can be provided as a name=value argument to the service. An ampersand-delimited list of arguments that can be used to test this service interface; when provided as the input to this interface, it will produce a legal, non-null response. When the interface supports GET, then the full query URL is formed by the concatenation of the base URL (given by the accessURL) and the value given by this testQuery element. The type of HTTP request, either GET or POST. A resource giving astronomical data in tabular form. While this includes classical astronomical catalogues, this resource is also appropriate for collections of observations or simulation results provided their metadata are available in a sufficiently structured form (e.g., Obscore, SSAP, etc). A description of the tables that are accessible through this service. Each schema name must be unique within a tableset. A service that interacts with astronomical data through one or more specified tables. This is the appropriate resource type for normal VO services, e.g., TAP, SSAP, SIAP, ConeSearch. The fully qualified name of the table. This name should include all catalogue or schema prefixes needed to sufficiently uniquely distinguish it in a query. In general, the format of the qualified name may depend on the context; however, when the table is intended to be queryable via ADQL, then the catalogue and schema qualifiers are delimited from the table name with dots (.). A descriptive, human-interpretable name for the table. This is used for display purposes. There is no requirement regarding uniqueness. A free-text description of the table's contents An identifier for a concept in a data model that the data in this table represent. The form of the utype string depends on the data model; common forms are sequences of dotted identifiers (e.g., in SSA) or URIs (e.g., in RegTAP). The approximate size of the table in rows. This is not expected to be exact. For instance, the estimates on table sizes databases keep for query planning purposes are suitable for this field. A description of a table column. A description of a foreign keys, one or more columns from the current table that can be used to join with another table. A name for the role this table plays. Recognized values include “output”, indicating this table is output from a query; “base_table”, indicating a table whose records represent the main subjects of its schema; and “view”, indicating that the table represents a useful combination or subset of other tables. Other values are allowed. A description of a parameter that places no restriction on the parameter's data type. As the parameter's data type is usually important, schemas normally employ a sub-class of this type rather than this type directly. The name of the parameter or column. A free-text description of a parameter's or column's contents. The unit associated with the values in the parameter or column. The name of a unified content descriptor that describes the scientific content of the parameter. There are no requirements for compliance with any particular UCD standard. An identifier for a concept in a data model that the data in this schema represent. The form of the utype string depends on the data model; common forms are sequences of dotted identifiers (e.g., in SSA) or URIs (e.g., in RegTAP). A description of a table parameter having a fixed data type. A type of data contained in the column A keyword representing traits of the column. Recognized values include “indexed”, “primary”, and “nullable”. While other values are allowed, the following semantics is defined by this specification: indexed – The column has an index on it for faster search against its values; primary – The values column in the column represent in total or in part a primary key for its table; nullable – the column may contain null or empty values. If true, the meaning and use of this parameter is reserved and defined by a standard model. If false, it represents a parameter specific to the data described If not provided, then the value is unknown. A description of a service or function parameter having a fixed data type. DALI-compliant services should use VOTableType here, others should use SimpleDataType. A type of data contained in the parameter. An indication of whether this parameter is required to be provided for the application or service to work properly. If true, the meaning and behavior of this parameter is reserved and defined by a standard interface. If false, it represents an implementation-specific parameter that effectively extends the behavior of the service or application. The parameter is required for the application or service to work properly. The parameter is optional but supported by the application or service. The parameter is not supported and thus is ignored by the application or service. A type (in the computer language sense) associated with a parameter with an arbitrary name This XML type is used as a parent for defining data types with a restricted set of names. The shape of the array that constitutes the value. Leave arraysize empty for scalar values. In version 1.1, this defaulted to 1, which was intended to indicate a scalar. This is now deprecated; an arraysize of 1 should be avoided now, the future interpretation, in accord with VOTable, will be “array of size 1”. A string that is used to delimit elements of an array value in InputParams. Unless specifically disallowed by the context, applications should allow optional spaces to appear in an actual data value before and after the delimiter (e.g., “1, 5” when delim=“,”). This should not be used for VOTable types; there, VOTable (typcially TABLEDATA) conventions for writing arrays are binding. The data value represented by this type can be interpreted as of a custom type identified by the value of this attribute. If an application does not recognize this extendedType, it should attempt to handle the value assuming the type given by the element's value. string is a recommended default type. This element may make use of the extendedSchema attribute to refine the identification of the type. extendedTypes without an extendedSchema mean VOTable xtypes as defined by DALI. An identifier for the schema that the value given by the extended attribute is drawn from. This attribute is normally ignored if the extendedType attribute is not present. A missing extendedSchema indicates that extendedType is a VOTable xtype. An expression of a the shape of a multi-dimensional array of the form LxNxM... where each value between gives the integer length of the array along a dimension. An asterisk (*) as the last dimension of the shape indicates that the length of the last axis is variable or undetermined. A data type restricted to a small set of names which is imprecise as to the format of the individual values. This set is intended for describing simple input parameters to a service or function. See vs:DataType. See vs:DataType. See vs:DataType. See vs:DataType. An abstract parent for a class of data types that can be used to specify the data type of a table column. A data type supported explicitly by the VOTable format See vs:DataType. See vs:DataType. See vs:DataType. See vs:DataType. An abstract parent for the specific data types supported by the Table Access Protocol. The length of the fixed-length value This corresponds to the size Column attribute in the TAP_SCHEMA and can be used with data types that are defined with a length (CHAR, BINARY). A data type supported explicitly by the Table Access Protocol (v1.0). This is deprecated in VODataService 1.2, and even TAP 1.0 services are encouraged to declare their columns using VOTableType. A description of standard space-time coordinate systems, positions, and regions. This resource type is deprecated, and no resource records of this type exist in the Registry. It will be removed in version 1.3 of VODataService. An STC description of coordinate systems, positions, and/or regions Each system, position, and region description should have a an XML ID assigned to it. Because the STC schema sets elementFormDefault="qualified", it is recommended that this element specify the STC default namespace via an xmlns namespace. A description of the mapping a foreign key -- a set of columns from one table -- to columns in another table. When foreign keys are declared in this way, clients can expect that joins constrained with the foreign keys are preformed efficiently (e.g., using an index). The fully qualified name (including catalogue and schema, as applicable) of the table that can be joined with the table containing this foreign key. A pair of column names, one from this table and one from the target table that should be used to join the tables in a query. A free-text description of what this key points to and what the relationship means. An identifier for a concept in a data model that the association enabled by this key represents. The form of the utype string depends on the data model; common forms are sequences of dotted identifiers (e.g., in SSA) or URIs (e.g., in RegTAP). A pair of columns that are used to join two tables. To do an inner join of data from the two tables, a query should include a constraint that sets the value from the first column equal to the value in the second column. This type assumes that it is used in the context of implied source (i.e., current) and target tables, as in the ForeignKey type's fkColumn. The unqualified name of the column from the current table. The unqualified name of the column from the target table. An interval of floating point numbers. This uses VOTable TABLEDATA serialisation, i.e., simply a pair of XSD floating point numbers separated by whitespace; note that software utilising non-XSD aware parsers has to perform whitespace normalisation itself here (in particular, for the internal whitespace).