PROGRAMS IN DATASTREAM
USING PROGRAMS, CODES, AND
DATATYPES WITHIN DATASTREAM
| Programs, in combination with correct data codes, are
what enable users of Datastream to obtain the specific
information they need. Programs give you access to
databases; codes and dataypes get you the data you want.
After one has chosen the general format of output you
want (Type of Request) and the general type of
information (Type of Data), Datastream displays the
programs available within those limits. The image above
shows what programs are available in time series
statistics for interest rates. Programs are numbered. By specifying the Type of Request and Type of Data, you are trying to find the Datastream program your search will require. To select a program from the list displayed, click on the text of the particular program item with the left mouse button of the computer. When you have done this, a program number will appear in the command line area of your Datastream window. You have successfully found part of the information required to execute a search. If you had known the number of the program you wished to use, at any time, you could have instead typed the program number into the main command line area and pressed enter. Pressing enter is the equivalent of double-clicking on the selected program with the left mouse button. For example, the 101 series provides international equity information, from detailed displays of current price and price related informaiton, to historical comparisons of a share price to its market sector. The 250 series provides current and historical futures market data from major international markets, and analysis program sto calculate hedge ratios, implied interest rates and cheapest deliverable securities. The 150 series provides access to macro economic information. The 301 series can be used to display large and diverse amounts of data in tabular format. The programs access all the Datastream databases subscribed to. Lists, functions, and symbolic expressions can be used with these programs. The 401 series provides a range of graphical display options. The 900 series are used to download data to other software packages. Having selected a program, the user will then be prompted to enter the parameters of the desired search. The types of input which will now be required can vary greatly with one's choice of program. Field level help is available by typing a question mark and pressing ENTER in any field. Because programs require many different types of input, it is sometimes necessary to try a program once in order to determine what variables will be requested. Most programs in Datastream will require the user to enter a code to specify what series of data is to be displayed, followed by several other variables which will determine which parts and how much of the series of data should be displayed (ie. monthly, from February through September of 1993). Finding correct data codes is equally important to finding correct programs. |
| All data items avialbe on Datastream have a numeric
or alpha-numeric code. Finding and selecting codes, for
example for equities, indices, or currencies, is a key
task when running Datastream programs. For this reason a
variety of methods for looking up codes is available to
you. The most important of these is Code Lookup.
This enables you to search for, select, and automatically
input codes within Datastream. The thousands of types of data that are maintained by Datastream are only manageable through the use of codes. Codes allow the user to specify with precision, exactly what the user wishes to obtain. Understanding codes and how they may be found is of the utmost importance if one is to learn how to use Datastream. Again, a code is simply a number or mnemonic assigned to a type of data to promote a uniformity in methods of series identification. For instance, if I wanted to know about the stock of Novell on a particular day, I could not simply select a program and enter the word Novell when prompted for an item to search for. I would first have to look up the code for Novell's stock, 729152. Finding the correct code, however, is a matter that requires care. |
| If you are familiar with programs in Datastream, you
will find that the first thing you will want to look up
when beginning a search is the data code you will be
using. There are two useful methods for looking up data
codes, the first accesses the Datastream mainframe, the
second uses locally stored indices. The first is a program for searching data codes by keyword that may be accessed by typing in the program HELP CODE?. This method is useful for its specificity and its currency because it accesses the remote server in London. One may enter a keyword (asterisks are valid for wildcard searches). Further criteria can be entered by specifying what type of financial instruments they wish to search (ie. equities, bonds, futures, etc.) and what currency they would wish the data to be denominated. By entering the word Novell and choosing to search equities in US currency, four possible codes are obtained. The desired data code is easily chosen. You can browse through many of the codes and mnemonics available on Help screens held on the Datastream mainframe. To select this facility type HELP CODE? at the Program number prompt, then press ENTER. Note that you cannot enter the codes displayed automatically into your program. You can either write it down, then type it in at the appropriate program prompt, or hghlight a code using your mouse, copy it to the clipboard, then insert it at the program prompt. The second method of searching for codes, referred to in the manuals as Code Lookup, may be used by clicking on the CODE BUTTON at the top, left hand side of the Datastream window. This program is similar to the program described above, but it differs in that it searches a collection of codes that resides on the particular computer you are using, so it may be faster. The method discussed previously will search for codes on the remote server, where they are likely to be most up to date. In this method you will need to chose a category for searching (for example, Equity Specific). Once you have chosen it you will be presented a screen that contains the following menu bar:
This lists the available menus. Below it you will find a tool bar with buttons that provide a fast and simple way to use Code Lookup's facilities:
For example, enter Program Numer '101A', Type of Request 'Reports', Type of Data 'Equities' and 'Latest data for up to 6 equities or a sector (with price/index chart)'. Having done this, when at the "ENTER UP TO 6 STOCKS/SECTORS/MARKETS SEPARATED BY SPACES" field, click on the code button. In the Find box you can type the first few letters of the company name and a list of companies beginning with those letters will appear. |
| The second part of finding a code is finding the
correct datatype. Codes specify the instrument you want
(e.g., equities, bonds, exchange rates and market
indices), and while every financial instrument has a
code, many instruments have hundreds of items of related
data. Each of these items is a datatype - a
mnemonic to specify that item. For example, use the code ICI
- and you get ICI's price. Use the code + datatype
combination ICI(DY) and you get ICI's
dividend yield. Thus, datatypes allow you to retrieve
different types of data within one series. Datatypes are
typically placed in brackets after the selected item. In
another example, the default representation of the series
code for the equity Novell is the closing price. If you
wanted the daily high price for Novell, you would have to
append the datatype PH to the Novell
series code @NOVL, making @NOVL(PH).
For help finding the datatypes available for codes in
Datastream use the program HELP DT? A
screen will be displayed that will allow you to choose
the appropriate Datatype catagory to find what you want
(datatypes are only available for equities, bonds, market
indices, company accounts, futures, options, and interest
and exchange rates). Programs, in combination with codes and datatypes get you the data you wnt. Datastream functions can be used to manipulate the data, for example, use the code BP to get BP's price. use the function and code combination MAV#(BP,3M) to return the three month average of BP's closing price. Functions can be combined to build expressions, giving you a pwerful mathematical capability. Expressions can be stored for future use. |
1997
Data and Program Library Service, University of Wisconsin-Madison