Provided by: stilts_3.1.5-1_all bug

NAME

       stilts-sqlskymatch - Crossmatches table on sky position against SQL table

SYNOPSIS

       stilts sqlskymatch [ifmt=<in-format>] [istream=true|false] [in=<table>] [icmd=<cmds>]
                          [ocmd=<cmds>]
                          [omode=out|meta|stats|count|cgi|discard|topcat|samp|tosql|gui]
                          [out=<out-table>] [ofmt=<out-format>] [ra=<expr>] [dec=<expr>]
                          [sr=<expr/deg>] [find=best|all|each] [usefoot=true|false]
                          [footnside=<int-value>] [copycols=<colid-list>] [scorecol=<col-name>]
                          [erract=abort|ignore|retry|retry<n>] [ostream=true|false]
                          [fixcols=none|dups|all] [suffix0=<label>] [suffix1=<label>] [db=<jdbc-
                          url>] [user=<value>] [password=<value>] [dbtable=<table-name>]
                          [dbra=<sql-col>] [dbdec=<sql-col>] [dbunit=deg|rad]
                          [tiling=hpx<K>|healpixnest<K>|healpixring<K>|htm<K>] [dbtile=<sql-col>]
                          [selectcols=<sql-cols>] [where=<sql-condition>] [preparesql=true|false]

DESCRIPTION

       sqlskymatch resembles coneskymatch, but instead of sending an HTTP query to a remote  cone
       search service for each match (i.e. each row of the input table), it executes an SQL query
       directly. The query is a SELECT statement with a WHERE clause which makes restrictions  on
       Right  Ascension  and  Declination  columns;  the  names of these columns must be given as
       parameters. The effect is that of a spatial join between a client-side table and  a  table
       stored in the database.

       This  command can only be used if you have access to an SQL database via JDBC. The details
       of how to configure a JDBC connection to a database are discussed in SUN/256  -  obviously
       you  will  need a database to connect to and appropriate read permissions on it as well as
       the relevant drivers.

       Note: this task was known as sqlcone in its experimental form in STILTS v1.3.

OPTIONS

       ifmt=<in-format>
              Specifies the format of the input table as specified by  parameter  in.  The  known
              formats  are  listed in SUN/256. This flag can be used if you know what format your
              table is in. If it has the special value (auto) (the default), then an attempt will
              be made to detect the format of the table automatically. This cannot always be done
              correctly however, in which case the program will exit  with  an  error  explaining
              which formats were attempted.

       istream=true|false
              If  set  true,  the  input  table  specified  by the in parameter will be read as a
              stream. It is necessary to give the ifmt parameter in this case. Depending  on  the
              required operations and processing mode, this may cause the read to fail (sometimes
              it is necessary to read the table more than once). It is not normally necessary  to
              set this flag; in most cases the data will be streamed automatically if that is the
              best thing to do. However it can sometimes  result  in  less  resource  usage  when
              processing large files in certain formats (such as VOTable).

       in=<table>
              The location of the input table. This may take one of the following forms:

                * A filename.

                * A URL.

                * The  special  value  "-", meaning standard input. In this case the input format
                  must be given explicitly using the ifmt parameter. Note that  not  all  formats
                  can be streamed in this way.

                * A  system  command  line  with  either  a  "<" character at the start, or a "|"
                  character at the end ("<syscmd" or "syscmd|"). This executes the given pipeline
                  and  reads  from its standard output. This will probably only work on unix-like
                  systems.
               In any case, compressed data in one of the supported  compression  formats  (gzip,
              Unix compress or bzip2) will be decompressed transparently.

       icmd=<cmds>
              Specifies  processing  to be performed on the input table as specified by parameter
              in, before any other processing has taken place. The value of this parameter is one
              or  more  of  the  filter commands described in SUN/256. If more than one is given,
              they must be separated  by  semicolon  characters  (";").  This  parameter  can  be
              repeated  multiple  times on the same command line to build up a list of processing
              steps. The sequence of commands given in this way defines the  processing  pipeline
              which is performed on the table.

              Commands may alteratively be supplied in an external file, by using the indirection
              character '@'. Thus a value of "@filename" causes the file filename to be read  for
              a  list of filter commands to execute. The commands in the file may be separated by
              newline characters and/or semicolons, and lines which are blank or which start with
              a '#' character are ignored.

       ocmd=<cmds>
              Specifies  processing  to  be  performed  on  the  output  table,  after  all other
              processing has taken place. The value of this parameter  is  one  or  more  of  the
              filter  commands  described  in  SUN/256.  If  more than one is given, they must be
              separated by semicolon characters (";"). This parameter can  be  repeated  multiple
              times on the same command line to build up a list of processing steps. The sequence
              of commands given in this way defines the processing pipeline which is performed on
              the table.

              Commands may alteratively be supplied in an external file, by using the indirection
              character '@'. Thus a value of "@filename" causes the file filename to be read  for
              a  list of filter commands to execute. The commands in the file may be separated by
              newline characters and/or semicolons, and lines which are blank or which start with
              a '#' character are ignored.

       omode=out|meta|stats|count|cgi|discard|topcat|samp|tosql|gui
              The  mode  in which the result table will be output. The default mode is out, which
              means that the result will be written as a new  table  to  disk  or  elsewhere,  as
              determined  by the out and ofmt parameters. However, there are other possibilities,
              which correspond to uses to which a table can be put other than outputting it, such
              as  displaying  metadata,  calculating  statistics, or populating a table in an SQL
              database. For some values of this parameter,  additional  parameters  (<mode-args>)
              are required to determine the exact behaviour.

              Possible values are

                * out

                * meta

                * stats

                * count

                * cgi

                * discard

                * topcat

                * samp

                * tosql

                * gui
               Use the help=omode flag or see SUN/256 for more information.

       out=<out-table>
              The  location of the output table. This is usually a filename to write to. If it is
              equal to the special value "-" (the default) the output table will  be  written  to
              standard output.

              This parameter must only be given if omode has its default value of "out".

       ofmt=<out-format>
              Specifies  the format in which the output table will be written (one of the ones in
              SUN/256 - matching is case-insensitive and you can use just the first few letters).
              If  it  has the special value "(auto)" (the default), then the output filename will
              be examined to try to guess what sort of file is required usually by looking at the
              extension. If it's not obvious from the filename what output format is intended, an
              error will result.

              This parameter must only be given if omode has its default value of "out".

       ra=<expr>
              Right ascension in degrees in the coordinate system for the position of each row of
              the  input  table.  This  may  simply  be  a column name, or it may be an algebraic
              expression calculated from columns as explained  in  SUN/256.  If  left  blank,  an
              attempt  is  made  to  guess  from  UCDs,  column  names  and unit annotations what
              expression to use.

       dec=<expr>
              Declination in degrees in the coordinate system for the position of each row of the
              input table. This may simply be a column name, or it may be an algebraic expression
              calculated from columns as explained in SUN/256. If left blank, an attempt is  made
              to guess from UCDs, column names and unit annotations what expression to use.

       sr=<expr/deg>
              Expression  which evaluates to the search radius in degrees for the request at each
              row of the input table. This will often be a constant numerical value, but  may  be
              the name or ID of a column in the input table, or a function involving one.

       find=best|all|each
              Determines which matches are retained.

                * best:  Only the matching query table row closest to the input table row will be
                  output.  Input  table  rows  with  no  matches  will  be  omitted.  (Note  this
                  corresponds  to  the best1 option in the pair matching commands, and best1 is a
                  permitted alias).

                * all: All query table rows which match the input table row will be output. Input
                  table rows with no matches will be omitted.

                * each:  There  will be one output table row for each input table row. If matches
                  are found, the closest one from the query table will be output, and in the case
                  of no matches, the query table columns will be blank.

       usefoot=true|false
              Determines  whether an attempt will be made to restrict searches in accordance with
              available footprint information. If this is set true, then before any of  the  per-
              row  queries are performed, an attempt may be made to acquire footprint information
              about the servce. If such information can be  obtained,  then  queries  which  fall
              outside  the footprint, and hence which are known to yield no results, are skipped.
              This can speed up the search considerably.

              Currently, the only footprints available are those provided by the CDS MOC  (Multi-
              Order  Coverage  map)  service,  which  covers  VizieR  and a few other cone search
              services.

       footnside=<int-value>
              Determines the HEALPix Nside parameter for use with the MOC footprint service. This
              tuning  parameter  determines  the resolution of the footprint if available. Larger
              values give better resolution,  hence  a  better  chance  of  avoiding  unnecessary
              queries,  but  processing them takes longer and retrieving and storing them is more
              expensive.

              The value must be a power of 2, and at the time of writing, the  MOC  service  will
              not supply footprints at resolutions greater than nside=512, so it should be <=512.

              Only used if usefoot=true.

       copycols=<colid-list>
              List  of  columns  from the input table which are to be copied to the output table.
              Each column identified here will be prepended to the columns of the combined output
              table, and its value for each row taken from the input table row which provided the
              parameters of the query which produced it. See SUN/256 for list syntax. The default
              setting  is  "*", which means that all columns from the input table are included in
              the output.

       scorecol=<col-name>
              Gives the name of a column in the output table to contain the distance between  the
              requested  central  position  and  the  actual  position  of  the returned row. The
              distance returned is an angular distance in degrees. If a null value is chosen,  no
              distance column will appear in the output table.

       erract=abort|ignore|retry|retry<n>
              Determines what will happen if any of the individual cone search requests fails. By
              default the task aborts. That may be the best thing to do, but  for  unreliable  or
              poorly implemented services you may find that some searches fail and others succeed
              so it can be best to continue operation in the face of a few failures. The  options
              are:

                * abort: Failure of any query terminates the task.

                * ignore:  Failure  of  a  query  is treated the same as a query which returns no
                  rows.

                * retry: Failed queries are retried until they succeed; an  increasing  delay  is
                  introduced  for  each failure. Use with care - if the failure is for some good,
                  or at  least  reproducible  reason  this  could  prevent  the  task  from  ever
                  completing.

                * retry<n>:  Failed  queries  are retried at most a fixed number <n> of times; an
                  increasing delay is introduced for each failure. If failures persist  the  task
                  terminates.

       ostream=true|false
              If  set true, this will cause the operation to stream on output, so that the output
              table is built up as the results are obtained from the  cone  search  service.  The
              disadvantage  of  this  is  that some output modes and formats need multiple passes
              through the data to work, so depending on the output destination, the operation may
              fail if this is set. Use with care (or be prepared for the operation to fail).

       fixcols=none|dups|all
              Determines  how  input  columns  are  renamed  before  use in the output table. The
              choices are:

                * none: columns are not renamed

                * dups: columns which would otherwise have duplicate names in the output will  be
                  renamed to indicate which table they came from

                * all: all columns will be renamed to indicate which table they came from
               If columns are renamed, the new ones are determined by suffix* parameters.

       suffix0=<label>
              If  the  fixcols  parameter  is set so that input columns are renamed for insertion
              into the output table, this parameter determines how the renaming is done. It gives
              a suffix which is appended to all renamed columns from the input table.

       suffix1=<label>
              If  the  fixcols  parameter  is set so that input columns are renamed for insertion
              into the output table, this parameter determines how the renaming is done. It gives
              a suffix which is appended to all renamed columns from the cone result table.

       db=<jdbc-url>
              URL   which   defines   a   connection   to   a   database.   This   has  the  form
              jdbc:<subprotocol>:<subname> - the  details  are  database-  and  driver-dependent.
              Consult  Sun's  JDBC  documentation and that for the particular JDBC driver you are
              using for details. Note that the relevant driver class will  need  to  be  on  your
              classpath  and  referenced  in  the  jdbc.drivers  system  property as well for the
              connection to be made.

       user=<value>
              User name for logging in to SQL database. Defaults to the current username.

       password=<value>
              Password for logging in to SQL database.

       dbtable=<table-name>
              The name of the table in the SQL database which provides the remote data.

       dbra=<sql-col>
              The name of a column in the SQL  database  table  dbtable  which  gives  the  right
              ascension. Units are given by dbunit.

       dbdec=<sql-col>
              The name of a column in the SQL database table dbtable which gives the declination.
              Units are given by dbunit.

       dbunit=deg|rad
              Units of the right ascension and declination columns  identified  in  the  database
              table. May be either deg[rees] (the default) or rad[ians].

       tiling=hpx<K>|healpixnest<K>|healpixring<K>|htm<K>
              Describes  the sky tiling scheme that is in use. One of the following values may be
              used:

                * hpxK: alias for healpixnestK

                * healpixnestK: HEALPix using the Nest scheme at order K

                * healpixringK: HEALPix using the Ring scheme at order K

                * htmK: Hierarchical Triangular Mesh at level K
               So for instance hpx5 or healpixnest5 would both indicate the HEALPix  NEST  tiling
              scheme at order 5.

              At  level  K, there are 12*4^K HEALPix pixels, or 8*4^K HTM pixels on the sky. More
              information about these tiling schemes can be found at  the  HEALPix  and  HTM  web
              sites.

       dbtile=<sql-col>
              The  name of a column in the SQL database table dbtable which contains a sky tiling
              pixel index. The tiling scheme is given by the tiling parameter. Use  of  a  tiling
              column  is  optional,  but if present (and if the column is indexed in the database
              table) it may serve to speed up  searches.  Set  to  null  if  the  database  table
              contains no tiling column or if you do not wish to use one.

       selectcols=<sql-cols>
              An  SQL  expression  for  the  list of columns to be selected from the table in the
              database. A value of "*" retrieves all columns.

       where=<sql-condition>
              An SQL expression further limiting the rows to be selected from the database.  This
              will  be  combined  with  the  constraints  on  position implied by the cone search
              centres and radii. The value of this parameter  should  just  be  a  condition,  it
              should  not  contain  the  WHERE  keyword.  A  null  value  indicates no additional
              criteria.

       preparesql=true|false
              If true, the JDBC connection  will  use  PreparedStatements  for  the  SQL  SELECTs
              otherwise  it  will  use  simple Statements. This is a tuning parameter and affects
              only performance. On some database/driver combinations it's a lot faster set  false
              (the default); on others it may be faster, who knows?

SEE ALSO

       stilts(1)

       If  the  package  stilts-doc  is installed, the full documentation SUN/256 is available in
       HTML format:
       file:///usr/share/doc/stilts-doc/sun256/index.html

VERSION

       STILTS version 3.1-5-debian

       This is the Debian version of Stilts, which lack the support  of  some  file  formats  and
       network protocols. For differences see
       file:///usr/share/doc/stilts/README.Debian

AUTHOR

       Mark Taylor (Bristol University)

                                             Mar 2017                       STILTS-SQLSKYMATCH(1)