Getting Started with TRANSACT (32247-90007)

98 Chapter6

Data Structures

In the Transact example, DEFINE(ITEM) (lines 1.1 to 1.23) deﬁnes the name, format, and

size of ﬁve data items. All ﬁve are of single word integer or binary format. In addition,

whenever storage space is reserved for enter, yes, or no, the space is initialized to contain

the values 0, 1, or 0, respectively. Note that DEFINE does not reserve space for the data

items. It more closely resembles the Pascal TYPE construct.

Lines 1.24 to 1.4 actually reserve space or make the data items known to Transact.

LIST(AUTO) in lines 2 and 3 also reserves space for data items. However, in this case the

data items have been previously deﬁned in Dictionary/V. Also the VPLUS form names

vorderhead and vorderline have been deﬁned in Dictionary/V. These lines are equivalent to

the following:

Figure 6-4. LIST(AUTO) Equivalent with LIST

Later on in the program there are verbs that input data from the VPLUS screens and

other verbs that update data in an IMAGE dataset. Examples from the program are:

Figure 6-5. VPLUS Default with no LIST=

Line 9 inputs data to the program from the VPLUS screen vorderline. There is nothing on

this line to indicate which data items to retrieve. In this default case, Transact looks at the

form deﬁnition in Dictionary/V to determine which data items are involved. If we wanted

to be explicit, we could have made this line read:

2 list order-no: |

| 2.1 cust-no: |

| 2.2 order-status: |

| 2.3 order-date; |

| 3 list line-no: |

| 3.1 part-number: |

| 3.2 quantity;

9 get(form) vorderline,fkey=lastkey;

10 put orderline,list=(order-no,

11 line-no,

12 part-number,

13 quantity);