Example: Modifying Data

The MODIFY statement is used to update a master dataset (Inventory) based on the values contained in a transaction dataset (InventoryAdd). Observations are matched by the 'partNumber' variable. If a matching observation is found in the master, it is updated (stock and price), and the received date is refreshed. If a transaction dataset observation does not exist in the master, it is added as a new observation. The code uses the automatic _IORC_ variables and the %SYSRC macro to handle different matching scenarios.

Data Analysis

Type : CREATION_INTERNE

The examples use generated data (datalines) for the 'Inventory' and 'InventoryAdd' datasets.

1 Code Block

PROC SORT / PROC PRINT Data

Explanation :
This block creates the 'Inventory' (master) and 'InventoryAdd' (transaction) datasets with inline data. Then, it sorts both datasets by 'partNumber' and displays them to show their content before any modification. This allows for a clear comparison with the results after the MODIFY operation.

Copied!

1	DATA Inventory;
2	INPUT partNumber $ partName $ stock price receivedDate :date9.;
3	FORMAT receivedDate date9.;
4	DATALINES;
5	K89R seal 34 245.00 07JUL2015
6	M4J7 sander 98 45.88 20JUN2015
7	LK43 filter 121 10.99 19MAY2016
8	MN21 brace 43 27.87 10AUG2016
9	BC85 clamp 80 9.55 16AUG2016
10	NCF3 valve 198 24.50 20MAR2016
11	KJ66 cutter 6 19.77 18JUN2016
12	UYN7 rod 211 11.55 09SEP2016
13	JD03 switch 383 13.99 09JAN2017
14	BV1E timer 26 34.50 03AUG2017
15	;
16	RUN;
17
18	DATA InventoryAdd;
19	INPUT partNumber $ partName $ newStock newPrice;
20	DATALINES;
21	AA11 hammer 55 32.26
22	BB22 wrench 21 17.35
23	BV1E timer 30 36.50
24	CC33 socket 7 22.19
25	K89R seal 6 247.50
26	KJ66 cutter 10 24.50
27	;
28	RUN;
29
30	PROC SORT DATA=Inventory; BY partNumber; RUN;
31	PROC SORT DATA=InventoryAdd; BY partNumber; RUN;
32	PROC PRINT DATA=Inventory; title "Inventory"; RUN;
33	PROC PRINT DATA=InventoryAdd; title "InventoryAdd"; RUN;

2 Code Block

DATA STEP (MODIFY)

Explanation :
This code block uses the MODIFY statement to update the 'Inventory' dataset using information from 'InventoryAdd'.
- `by partNumber;`: Matches observations from both datasets by the 'partNumber' variable.
- `select (_iorc_);`: Uses the automatic _IORC_ variable to determine the matching result.
- `when (%sysrc(_sok))`: If a match is found (_sok), stock is increased, price is updated, received date is set to today(), and the observation is replaced (`replace;`).
- `when (%sysrc(_dsenmr))`: If no match is found (_dsenmr), a new observation is created with the new stock, new price, and today's received date, then added (`output;`). `_error_=0;` is used to prevent the DATA step from stopping due to an error.
- `otherwise`: Handles unexpected I/O errors.
After modification, the 'Inventory' dataset is sorted and displayed to show the changes.

Copied!

1	DATA Inventory;
2	modify Inventory InventoryAdd;
3	BY partNumber;
4	select (_iorc_);
5	when (%sysrc(_sok))DO;
6	stock = stock + newStock;
7	price=newPrice;
8	receivedDate = today();
9	replace;
10	END;
11	when (%sysrc(_dsenmr)) DO;
12	stock=newStock;
13	price=newPrice;
14	receivedDate=today();
15	OUTPUT;
16	_error_=0;
17	END;
18	otherwise DO;
19	put "An unexpected I/O error has occurred.";
20	_error_ = 0;
21	stop;
22	END;
23	END;
24	RUN;
25	PROC SORT DATA=Inventory;
26	BY partNumber;
27	RUN;
28	PROC PRINT DATA=Inventory;
29	title "Modified Inventory Data Set Sorted by partNumber";
30	RUN;
31	QUIT;

This material is provided "as is" by We Are Cas. There are no warranties, expressed or implied, as to merchantability or fitness for a particular purpose regarding the materials or code contained herein. We Are Cas is not responsible for errors in this material as it now exists or will exist, nor does We Are Cas provide technical support for it.

Retour à la liste