Transcript Classnotes 2

iSeries Database Files
• Physical Files
• Logical Files
*FILE
*FILE
PF-DTA
LF
Physical Files
• It is an as/400 file used to store data or
source code.
• Physical files have members.
• The members contain data or source
code.
• Source physical files have many
members eg. One for each program
• Data physical files usually have 1
member (but can have more)
Data Files
Files, Records, Fields
• A file member contains one or more records
• A record is made up of one or more fields
which give it its record format or file
description
• Each field contains a unique piece of
information e.g. student no, first name, last
name, address, telephone no, etc.
Examples of Files, Records, Fields
• A customer file is made up of customer records (1 per
customer).
• Each customer record has fields containing unique
pieces of info about a particular customer
e.g. customer name, address, sales territory,billing
info, shipping instructions,
credit information
• Student file - student records (1 per student)- student
info: name, address...
More Examples of Files, Records,
Fields
• Parts file - parts records - info about part:
part number, description, warehouse location,
supplier, quantity on hand,
• Payroll file - payroll records - payroll info for
employees: employee number, name, date of hire,
hourly or salary, hourly rate or annual salary, income
tax info….
How do we create data
physical files?
Creating Physical Data Files
• Creating an AS/400 data file is very similar to creating a
program:
– Write the source code (the source code will describe what
the file will look like). The source code is stored in a member
in a source file.
– Compile the source code (this creates a *file object).
Tools for Describing Database
Files
• Data Description Specifications (DDS)
– AS/400 language to create source code for Files
• Others:
– SQL (Structured Query Language), (you will do this in DB2
course)
Using DDS
• Source code is entered into a source physical file member in the
form of DDS statements. This is done using the iSeries editor
SEU
• The DDS statements describe each field of the record in detail
e.g. field name, data type (numeric, character, packed numeric,
etc), standard column headings, etc.
• The source file for DDS is QDDSSRC.
Example of DDS
Columns . . . :
1 71
Browse
DMENKEN/QDDSSRC
SEU==>
STUPF
FMT PF .....A..........T.Name++++++RLen++TDpB......Functions++++++++++++++++++
*************** Beginning of data *************************************
0001.00
0002.00
A
R STUPFR
0003.00
A
SOCINS
9S 0
COLHDG('Social' 'Insurance'
0004.00
A
FNAME
15A
COLHDG('First' 'Name')
0005.00
A
LNAME
20A
COLHDG('Last' 'Name')
0006.00
PHONE
10S
COLHDG('Phone' 'No.')
0007.00
A
ADDR1
25A
COLHDG('Street' 'Address')
0008.00
A
ADDR2
25A
COLHDG('City')
0009.00
A
ZIP
5S 0
COLHDG('Zip Code')
****************** End of data ****************************************
Creating a Database File
• Create the source file (CRTSRCPF) which is named QDDSSRC
(only done once)
• Create a source member, type PF
• Enter the source code using SEU
• Save source code and compile to create the file
• Put data into the file.
• The source type:
– tells SEU what type of source you are
creating e.g. TXT, PF, LF, etc. Used for
prompting and checking the syntax
– will tell PDM which compiler to use when
creating the object.
Entering DDS code
• First statement is the Record Format
statement. Put an R in the Name Type field
and the record name in the Name field.
• Then enter the field info (field name, length,
data type, decimal positions, standard column
heading) (nothing in Name Type field)
Demo
Compiling the Source Code
• CRTPF command or Option 14 in PDM
takes the source code and creates the
object i.e. the physical file
the physical file is what holds the data
How do you know if the
compile worked???
• DSPMSG- you will have a message which
tells you whether your job completed normally
or not.
• An output file is created with each compile
(the compile listing) which tells you what
happened. READ it!
• Where is that output file??
– In your output queue!!
Question!
• If the compile ended abnormally, what
do you do? How can you find out why?
Unique feature of iSeries Files
• The record description is stored with the
file object (externally described file)
• It can then be used by iSeries utilities
• The record description does not have to
be coded in programs that use it.
• Can be viewed using DSPFD, DSPFFD
Entering data
• If the compile was successful, you will
have a new object in your library, a
physical file.
• To enter data into that file, use DFU,
Data File Utility
DFU
• STRDFU, then option 5
• PDM option 18
or…
• F10 to enter new records (entry mode)
• F11 to change records (change mode),
page up and down to find records
• F23 to delete a record
Viewing records
• RUNQRY QRYFILE(filename)
• DSPPFM
filename