U.S. Bureau of the Census
                              Economic Census Staff
                             Washington, D.C.  20233


     EXTRACT TUTORIAL #2 (EXTutor 2)

     Adding labels, selecting records,                      November 7, 1991
        refining the screen display

     =====================================================================
     CONTACT:      Bob Marske  or                          (301) 763-1792
                   Paul Zeisset


     ABSTRACT:     {The following was designed as the script for a training
                   presentation.  It may also be used as a self-directed
                   tutorial in EXTRACT usage.}

                   {This tutorial covers adding labels, selecting records in
                   more sophisticated ways, and refining the screen display. 
                   It requires Economic Census CD-ROM 1C, 1D or 1E and
                   EXTRACT 1.3 or later.} 

     TIME REQUIRED:  30 minutes to 1 hour

     =====================================================================

          [Note:  while the following is set up to use a SC87A1 geographic
          area series file on 1987 Economic Censuses CD-ROM Volume 1, it is
          easily adaptable for use with the Volume 2 ZIP code disk, for
          example, with a SC87Z1 file.]

          In Tutorial #1, we did a very straightforward selection of items
          and records in a simple file.  Let's see what we can do with files
          that present more complex options.

     STARTING THE PROGRAM

     1.   We will start EXTRACT using the parameters we saved in the last
          session.

          {Type:} EXECON <enter>, {then press} <enter> {again after viewing
          the opening screen.}

     2.   {If you did not save drive designations during Tutorial #1, the
          system will prompt you for them here.}

     3.   {On the Select a Catalog screen,} <PgDn> {and cursor to the
          SC87A1__ catalog, and select it by pressing} <enter>.

     4.   The help screen now describes this as a different kind of file,
          one in which each kind of business is on a separate record--like
          lines going down a table.

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     5.   {On the Select a File menu, select a state and press} <enter>.

     6.   {From the main menu, type:} 1 <enter> {to Select Items.}

          {Put an X next to SVC87KB,ESTAB, RCPT, and EMPLOYE.}

          {Press} <esc>.

     4.   {At the main menu, type:} 6 <enter> {to Display to Screen.}

          On this display each line is identified by a kind-of-business
          code, which is not very descriptive. Therefore we are going to
          have to go back to the main menu and add the labels from another
          file.

          {Press} <esc>.

     ADDING LABELS FOR KIND-OF-BUSINESS

     1.   {At the main menu, type:} 3 <enter> {to Add Labels.}

          This menu shows each of the code variables that have alphabetic
          labels associated with it.  We have already selected a particular
          county, so we can skip by the geographic labels and select a label
          for the kind of business.

          {Cursor to SVC87KB, and press} <enter>.

     2.   Some variables, like this one, give us more than one label to
          choose from.  Longer labels are more descriptive, while short ones
          leave space for more data.  Let's pick the 40-character label.

          {Cursor to TEXT40 and press} <enter>.

     3.   {At the main menu, type:} 6 <enter> {to redisplay the data.}

          This looks more like the kind of result we had in mind, more or
          less like a printed table.
















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     SELECTING RECORDS FOR A COUNTY

     1.   {Type:} 2 <enter> {to Select Records.}

          Not all selection variables are equally efficient in finding data. 
          Let's say that we want to find data for [city], and we see that
          there are two kinds of place code available--a census place code
          PLACE, and a FIPS place code PLACEFIP. Notice, however, that PLACE
          has an asterisk by it, while PLACEFIP does not.  The "*" denotes
          those variables for which indexes are available, and that is
          directly related to how fast we can accomplish the searching
          process.

          Let's pick data for one county, using the COUNTY variable.

          {Cursor down to COUNTY, type} S, {and press} <esc> {to go to the
          next screen.}

          [If you are using Economic Census disc 1C, do not select on PLACE
          unless you have installed CD1CSUP2.] 

     2.   {In Select Records Screen 2, put an X next to the particular
          county of interest.}

     3.   SPEED-UP SCREEN

          Here is something you may not have expected.  The system tells us
          that it can speed up retrieval if we pick one of the categories of
          RECTYPE.  We select data for a county.

          {Cursor to 06 County, and type:} X.

             You may be puzzled as to why the system asked that extra
             question, particularly when the answer seems obvious.  In fact,
             county codes are attached to place records as well as county
             records, so your answer does make a difference.

             EXTRACT makes use of existing "indexes" on the CD-ROM whenever
             it can to speed the process of finding specific data.  In this
             case it found that in order to use a particular index, it had
             to know both the county and the record type, so it prompted us
             for the missing piece of information.

             If you happen to select a RECTYPE that is not valid in
             combination with the rest of your selection criteria (e.g., if
             you specified a RECTYPE for State, when you had already
             specified a particular county code), then the program will not
             find any of the data you want.

             EXTRACT uses the information supplied "to speed up retrieval"
             only for the purpose of finding the first eligible record. 
             Thus, the index is "turned off" as soon as the first eligible
             record is found, and data are presented in the original
             sequence of the file.

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          {Press} <esc>.

          If you have picked a small county, the system may display "No
          records found" because the SC87A1 files include only counties with
          350 or more service establishments.  In this case you will need to
          repeat the record-selection procedure with a larger county.

     4.   {At the main menu, type} 6 <enter> {to redisplay the data.}

          This shows us the data for the county selected.  Note that its
          name has been introduced as a subheading.

     5.   You remember that we looked at definitions before in the Select
          Items screen.  Definitions are also accessible here for many, but
          not all, files.

          {Cursor to the EMPLOYE column and press} D.  {After viewing the
          definition, press} <esc>.

          Definitions are also associated with some labels, as in the case
          of this kind-of-business definition.

          {Cursor to the left-hand text column and highlight a particular
          kind-of-business category you want defined and press} D.  {If a
          message at the bottom says no definition available, move to a
          higher level item and try again.}

          {Press} <esc> to return to the data display, and <esc> again to
          return to the main menu.

























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     RESELECTING RECORDS TO LOOK AT A SINGLE KIND OF BUSINESS ACROSS
     COUNTIES

     So far we have been dealing with information much like we would find it
     in a printed report.  But let's look at the data another way.  Let's
     look at the distribution of computer-related services [or substitute
     another kind of business] among all areas in the state.

     1.   {Press} 2 <enter> {to Select Records.}

     2.   To look at records for one kind of business, we need to select on
          SVC87KB.

          {Cursor to SVC87KB, type:} S, {then press} <esc>.

     3.   The system now presents us a list of all possible kind of business
          codes, from which we want to select computer-related services.

          The code [for SVC87KB] we are interested in does not display on
          the screen, so we could can page down until we find it, as before. 
          At the same time, EXTRACT offers some shortcuts to help you find
          codes faster.  One way we can find out about these shortcuts is to
          press the help key <F1> or <H>.

          {Press} <F1>.

     4.   HELP SCREEN

          EXTRACT's help system is context sensitive, that is, it gives you
          help specific to where you are in the program.

          At the bottom of this help screen are listed several "special
          options".

          D  is for <D>efinition, but we don't need that right now.

          J  is to <J>ump to a specific code, if we knew it in advance, but
             we don't so that doesn't apply.

          L  is for <L>ocate, and it finds the a particular character string
             at the beginning of the label.  Since these labels feature SIC
             codes at the beginning, we could use this feature to Locate a
             particular SIC code.

             This feature would have been quite handy earlier when we were
             looking for a particular county.  We could simply have typed in
             L and then the name of the county.

          R  is for <R>ange, which we generally use either when we want to
             specify a range of codes or, perhaps, numeric values (e.g.,
             records where sales exceed $10 million).

          W  is for <W>ord search, and this should be just what we need.


                                                  5


          {Press} <enter> {to return to the select-records menu.}


     5.   {Type:} W, {and enter} computer {in the word-search window at the
          bottom of the screen.}

          It takes a minute or so for the system to search through all of
          the labels for the word "computer", but it eventually comes up
          with a list of all of the SICs in the 737 group.

          Put an X next to code 185.

             Entries containing the word "computer" all happened to be
             together.

               Just for fun, let's also do a word search on "rental".

             {Type:} W {then} rental {and press} <delete> {until the last
             two characters of "computer" are erased, then} <enter>.

             As you can see, this Word Search feature can be quite powerful. 
             Still, its success depends on how items are worded.  If we had
             entered "leasing", you can see that Word Search would have
             missed code 174 (where leasing is abbreviated "leas", and
             several other codes where the word "leasing" was not used at
             all (175, 176, 178, and 195) even though it is implied.

             As long as we don't check anything here, our previous selection
             of "Computer and data processing services" remains intact.

          {Press} <esc> {to return to the main menu.}

     6.   {Type:} 6 <enter> {to display to the screen.}

          Displaying the data to the screen is not very useful at this
          point.  The kind-of-business labels we have added no longer
          distinguish what data we are dealing with.  We need names or codes
          for geographic areas instead.

          {Press} <esc>.

     7.   {Type:} 1 <enter> {to select items again.}

          {Add X's by MSA, COUNTY, and RECTYPE, then press} <esc>.

     8.   {Type:} 3 <enter> {to add labels.}

          The system now warns you that unless you press S for <S>ave you
          will no longer have the SVC87KB labels.  That is fine, since we
          are restricting ourselves to one kind of business, so we do not
          type S.

          {Cursor to COUNTY and press} <enter>.


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     9.   At the bottom of the second labelling screen, we can see that
          there is an option to show additional fields, and another to allow
          multiple labels.  Let's exercise both.

          {Type:} A {to show all fields, then} M {to allow multiple labels.}

          With the longer list, we now have to search farther to find the
          20-character version of the county name.

          {Cursor down to TEXT20.  Press} <enter>.

          Now a "greater-than" sign > appears at the left of TEXT20, and the
          system lets us pick another label.  We can cursor down to POP87,
          and add 1987 population figures to our display of service industry
          data.

          {Cursor down to POP87, and press} <enter>.
          {Press} <esc> {to return to the main menu.}

     10.  {Type:} 6 {to display the data.}

          This gives us the distribution of computer data processing
          services within the state--at least in those areas for which
          detailed kinds of business are shown.

          Note that there are lines without a county name that have a
          RECTYPE of 04--these are records for metropolitan areas. (In fact,
          the text may say "United States" since that is the label
          associated with zeroes for state and county code.)  We have to go
          to the end of that list before the counties start.  (In a state
          without many large counties, you may also see records with RECTYPE
          of 07 for places.)

          Note that 1987 population has been added to the display by way of
          the labelling feature.  There are a few data items in addition to
          labels in some of the label files.  To see them we used the <A>ll
          fields option on the second Add Labels screen.

     11.  ADDING A SECOND SET OF LABELS  [Optional]

          [At this point you could also add MSA labels, TEXT10 suggested, to
          the display.  You have to type S first to save the county labels
          before proceeding.  After selecting 6 at the main menu, you will
          see that data display is MUCH slower when two sets of labels are
          used at the same time.]










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     EXTRACTING DATA TO A .DBF FILE

     This set of records might just be a group we want to refer back to, so
     let's save that to a file that EXTRACT can continue to use.

     1.   {Type:} 8 <enter> {to Extract the data to a file.}

     2.   {Type:} 1 {to select the DBF file option.}

          {Enter a file name, including drive and directory, but not any
          extension, e.g.,} c:\work\compsvcs.

          The system prompts us for a description for our "My_Files"
          catalog.  You can take the one listed, you can edit it by
          cursoring to something you want to change, or you can retype the
          line.  

          {Type:} Computer data processing services in [state] [date]
          <enter>.

          The system will work for a while, first extracting the appropriate
          records, and then in a second pass adding the appropriate labels. 
          If you have added two sets of labels, this step can take quite a
          while.

     3.   When the system is finished, it offers you the choice of returning
          to the original file or of going directly to the newly created
          file.  Normally we would take this shortcut to the new file.  But
          first let's see another technique for retrieving the file we have
          just created.

          {Type} 1 <enter> {to return to the main menu.}

     4.   We can locate the .DBF files we create through the file selection
          menu.

          {Type:} 9 <enter> {to Return to the File Selection Menu.}

     5.   {Press} <PgDn> {until you see the MY_FILES catalog, and press}
          <enter> {to select it.}

          Note that the description we put in is available to help us select
          among a series of files.

          {Cursor to the desired file, if it is not already highlighted, and
          press} <enter>.









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     6.   {Type:} 6 <enter> {to display to the screen.}

          At this point the display looks just like the one we had before,
          except that this time there was no waiting while it built up the
          screen.  That is because it is not having to slow down as it
          filters out records that do not qualify, and because the system is
          working off the hard disc (a fast device) rather than off a CD-ROM
          (a slow device).

          {Press} <esc>.

     7.   {Type:} 1 <enter> {to bring up the Select Items screen.}

          The system has created a customized data dictionary for our new
          database file.  Here we can see that there are fewer items to
          choose from.

          {Press} <esc> {to leave the item list unchanged and return to the
          main menu.}

     8.   If we want to add another label to the file, we could do so with
          option 3.  

          If we wanted to cut of some of the records, for instance
          eliminating all but the county records, we could do so with option
          2.

          But if we decided at this point that we wanted more data rather
          than less, such as one of the flags we saw in the original file,
          we would have to reselect the original file, and repeat most of
          our original steps.  

     9.   {If you are finished, type:} Q {to quit.}






















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     PRACTICE PROBLEMS

     1.   What are the three most important merchandise lines, other than
          groceries, sold by food stores (SIC 54) in the Albany-Schenectady-
          Troy, NY MSA?

          Hints:  use the RC87L___ catalog and the RC87L1MM file; select
          items to include RTL87ML, ESTAB, SALES, and SALPALL; add labels
          for RTL87ML; and select records on MSA and RTL87KB.  You will need
          to know that the Albany metropolitan area does not include any
          primary metropolitan statistical areas.

          If you want to carry this further, compare your list of top
          selling merchandise lines in this metro area in 1987 to
          corresponding figures for 1982 and 1977 (see data under a separate
          catalog) or to nationwide figures in RC87L1XS.

     2.   What kinds of retail business are present in your own ZIP code, or
          one familiar to you?

          Hints:  Using a CD-ROM in the Economic Censuses Volume 2 series,
          specify the RC87Z1__ catalog and your state; select items to
          include ZIP, ESTAB, ESALE1, ESALE100, ESALE250, ESALE500, and
          ESALE1M; add labels for RTL87KB; and select records on ZIP,
          specifying your ZIP code as both the minimum and maximum value of
          the range.





























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