rfc2259.txt

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      select * from People wher surname = "Elliott";
      .
      730 00000001a000022 e syntax error

      730 00000001a000027 e syntax error

      730 00000001a000037 e syntax error

      730 00000001a000039 e syntax error


      250 All queries processed

       Figure 3: Graphical User Interface Program Queries Server

   ---------------------------------------------------------------------

2.4 User Changes Mind

   An exuberant user decides to search everywhere for family members,
   then look up a friend who works at Epic Systems, and finally search
   everywhere for an old school friend.  Once the query set starts, the
   user realizes the folly of searching everywhere, stops the first




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RFC 2259                          SNQP                      January 1998


   query, executes the second query and then stops executing the query
   block.  This scenario is illustrated in Figure 4.  The t-bound is
   represented by <time> in this scenario due to space restrictions.

   ---------------------------------------------------------------------

      query
      350 Send the query text, end with .

      select * from people where surname = "Smith";
      select given_name, surname, email from people
             where surname = "Elliott"
             and organization = "Epic Systems*";
      select * from people where surname = "Brown";
      .
      next

      352 Starting next query.  Any pending responses discarded.

      351 Partial response follows, ended with .

      Given_Name: Jim
      Surname: Elliott
      Email: [e-mail]

      .
      352 Beginning next query.  Previous current through <time>.

      stop

      251 All pending queries and responses discarded


          Figure 4: User Changes Mind About Submitted Queries

   ---------------------------------------------------------------------

2.5 User Worries About Costs

   In Figure 5a, the exuberant user decides to apply more caution, and
   asks for advice on searching for a friend named "Susan Brown".  The
   user can not recall the name of the organization where Susan works,
   but remembers that the state name begins with "I".  The advice
   response lists the locations of the data repositories that will be
   contacted. These locations can be supplied to the SNQP server using
   the "source" attribute.  Each location is followed by a blank and a
   descriptive phrase for the data repository. Continuing in Figure 5b,
   the SNQP server also supplies a list of attributes that may constrain



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RFC 2259                          SNQP                      January 1998


   the query further.  The user recognizes the name Northeastern, and
   submits the query directly to that location.  The user could also
   have added "organization = "Northeastern*"" to the original query.
   Other advice options are described in Section 3.

   ---------------------------------------------------------------------

      advice
      214 Basic advice enabled.  Query responses disabled.

      query
      350 Send the query text, end with .

      select * from people where surname = "Brown" and
                                 given_name = "Susan" and
                                 state_or_province = "I*";
      .

      354 The query will contact 8 data repositories, ended with .
      ccso://ns.dacc.cc.il.us:105/* Danville Area Community College
      ccso://ns.eiu.bgu.edu:105/* Eastern Illinois University
      ccso://ns.ilstu.edu:105/* Illinois State University
      ccso://ns.imsa.edu:105/* Illinois Math and Science Academy
      ccso://ns.ne.edu:105/* Northeastern Illinois University
      ccso://ns.uiuc.edu:105/* University of Illinois at Urbana-Champaign
      ccso://ns.iup.edu:105/* Indiana University of Pennsylvania
      ccso://ph.indstate.edu:105/* Indiana State University
      .


          Figure 5a: User Asks About Costs Before Executing Query

   ---------------------------------------------------------------------


















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   ---------------------------------------------------------------------

      355 There are 8 attributes that may constrain the query, ended with .
      Organization
      Department
      Email
      State_or_Province
      Country
      Postal_Code
      Phone
      Source
      .

      250 All queries processed.  Current through 12-Jun-1996 22:35 EDT.

      noadvice
      214 Query responses returned.  Advice disabled.

      query
      350 Send the query text, end with .

      select * from people where surname = "Brown" and
                              given_name = "Susan" and
                                 state_or_province = "I*" and
                                 source ="ccso://ns.neiu.bgu.edu:105/*";
      .

      351 Partial response follows, ended with .

      Given_Name: Susan
      Middle_Name: W.
      Surname: Brown
      Organization: Northeastern Illinois University
      Email: [e-mail]
      Source: ccso://ne.edu:105/alias=SW-Brown

      .
      250 All queries processed.  Current through 12-Jun-1996 22:35 EDT.

          Figure 5b: User Asks About Costs Before Executing Query

   ---------------------------------------------------------------------









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RFC 2259                          SNQP                      January 1998


3. Commands

   SNQP commands are case insensitive and terminated with a newline <LF>
   or carriage return <CR>.  In the following descriptions, SNQP
   commands are in upper case and SNQP replies are in mixed case.  Items
   in a command list are separated by blanks.

   Most SNQP replies are short.  They have a rely code (see Section 4),
   followed by a continuation character and reply text.  If the
   continuation character is blank, the reply is complete.  If the
   continuation character is a dash ("-"), the reply continues on the
   next line.  Text within the reply can vary, but the reply code
   remains the same.  A two line reply example is given below:

   ---------------------------------------------------------------------

      nnn-Message1
      nnn Message2

   ---------------------------------------------------------------------

   In some cases commands or replies may be long, so these
   commands/replies use the '.'-terminated block structure that is used
   for message bodies in SMTP. Blocks are comprised of lines of text
   that constitute the command/reply.  Blocks are terminated with a
   period on a line by itself.

   SNQP generally ignores blank lines in both directions, except that
   blanks lines separate tuples within query response blocks.

   Whenever a time is listed in a command or response, it has the
   format:

   ---------------------------------------------------------------------

   DD-MMM-YYYY HH:MM ZZZ

   ---------------------------------------------------------------------

   where DD is the day, MMM are the first three characters of the month,
   YYYY is the year, HH the hours on a 24 hour clock, MM the minutes,
   and ZZZ the commonly used US timezone abbreviations.  If time zone is
   unspecified in a command, the timezone of the SNQP server is assumed.

   SNQP servers support a source attribute in every relation.  In
   queries, the source attribute directs the SNQP server to a particular
   data repository.  In query responses, the source attribute indicates
   the origin of the information in a tuple.  In advice and error



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   messages, the source attribute is provided so the client can contact
   the source in later queries.  The source attribute has two possible
   forms:

   ---------------------------------------------------------------------

   <protocol>://<domain-name>:<port>

   <protocol>://<domain-name>:<port>/<tuple-id>

   ---------------------------------------------------------------------

   <protocol> identifies the protocol used to contact the data
   repository. The data repository can be (was) contacted at <domain-
   name> and <port>.  When present, <tuple-id> identifies a specific
   entry in the data repository.  It is missing when the data repository
   does not have an attribute that uniquely identifies its entries.
   Although the source string is similar to a URL, the protocols listed
   may or may not be supported by World-Wide Web browsers.  An effort
   should be made to keep the protocol identifiers consistent with
   accepted standards, but in the end they are specific to SNQP servers.

   When a connection is established with an SNQP server, the server
   returns the following greeting where <domain-name> is the domain name
   of the server host, e.g.  nomen.research.bell-labs.com,  and
   <service-name> is the name of the service, e.g. Nomenclator:

   ---------------------------------------------------------------------

      220 <domain-name> <snqp-service-name> Query Service ready

   ---------------------------------------------------------------------

   The following sections describe each command in detail.  The commands
   are ordered alphabetically.  Typical reply messages are explained
   with each command.  Exceptional error conditions, for example system
   errors or rejection of connections due to load, may sometimes occur.
   These error replies are documented in Section 4.













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RFC 2259                          SNQP                      January 1998


3.1 Advice

   ---------------------------------------------------------------------

      ADVICE
      214 Basic advice enabled. Query responses disabled.
      514 Advice not available

      ADVICE <RELATION> <ATTRIBUTE>
      214 Advice enabled for "<attribute>" in "<relation>"
      553 Unknown relation
      554 Unknown attribute
      514 Advice not available for "<attribute>"

   ---------------------------------------------------------------------

   In all cases, advice disables query searches. When queries are
   submitted, advice is returned about the cost of the query or ways of
   constraining the query further.  There are two forms of the advice
   command.

   The first form of command does not include an attribute name.  When
   an SQL query is processed, the SNQP server returns a list of data
   repositories that it will contact.  It also returns a list of
   attributes that may constrain the query further.  The specific values
   of the attributes will determine whether the query is constrained
   further.  If advice is not available from the server, an error is
   returned.

   The second form of advice includes the name of a relation and the
   name of an attribute in that relation.  SQL queries return a list of
   possible values for the attribute.  The list may be complete, or may
   only include values that are known to constrain the search.  This
   distinction is described further in the query command.  If advice is
   not available on the attribute or the relation or attribute is
   unknown, an error is returned.  When advice is not available on an
   attribute, basic advice and advice on other attributes may be
   available.

   Basic advice and advice for one or more attributes can be enabled
   simultaneously. They are not mutually exclusive.

   The advice command is useful to application programs which present
   lists of alternatives to the user.  A query-form program can enable
   advice for an attribute, submit an empty query, and obtain the list
   of options for the attribute.  The list will indicate whether it is a
   full list of all values for the attribute, or a constraint list of




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RFC 2259                          SNQP                      January 1998


   only those values known to constrain queries.  The program can use
   full lists to create a selection menu on its query form.  A program
   can also enable basic advice, submit the query, and then ask the user
   to select the data repositories to search from the resulting list.

3.2 Attributes

   ---------------------------------------------------------------------

      ATTRIBUTES <RELATION> <TIME>
      212-There are <n> attributes in relation "<RELATION>":
      212-<Attribute-name>
      212-<Attribute-name>
      212 Current through <TIME>

      553 Unknown relation.  Current through <TIME>.
      556 T-bounds not supported

   ---------------------------------------------------------------------

   The attributes command lists the attributes defined for the given
   relation.  Since characteristics of relations may be defined outside
   the SNQP server and cached there, the user may ask for an answer that
   is more recent than <TIME>.  The SNQP server will endeavor to provide
   this information.  The first line of the reply notes the number of
   attributes <n>.  Subsequent lines list the attribute names.  The
   information in the response is current through the time returned, but
   may have changed after that time.  Accepting requests to improve a
   t-bound and indicating the t-bound of the result are optional for
   SNQP servers.

   If the relation is unknown, an error is returned.  If <TIME> is
   submitted when t-bounds are not supported, an error is returned.

3.3 Compare

   ---------------------------------------------------------------------

      COMPARE <COMPARISON-TYPE>
      213 Performing <COMPARISON-TYPE> comparisons

      555 Unknown comparison type

   ---------------------------------------------------------------------

   The compare command lists the type of equality comparison performed
   for SQL queries.  The compare command can be followed by a comparison
   type to set the type.  Reply 555 is returned if the comparison type



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