Key-Value Manager in a Dataset

The `%mp_setkeyvalue` macro is a flexible tool for maintaining structured information as key-value pairs in a SAS^© dataset. If the target dataset (`libds=`) does not exist, it initializes a new table with `key` columns (char $64 with unique index), `valc` (char $2048 for textual values), `valn` (num 8 for numeric values), and `type` (char $1 to indicate the stored value type). The use of a unique index on the `key` column ensures data integrity. It then uses `PROC SQL` to first delete any existing entry for the given `key`, ensuring only one entry exists for each key. Then, it inserts the new key-value pair. The `type` parameter (C for character by default, N for numeric) determines which column (`valc` or `valn`) the value is stored in. This approach is useful for configuration tables, dynamic parameters, or process tracking.

Data Analysis

Type : CREATION_INTERNE

The macro creates and manipulates an internal SAS dataset (default 'work.mp_setkeyvalue') or a user-specified dataset. It does not read data from external sources (files, external databases) or from SASHELP datasets, with the potential exception of the macro `%mf_existds` which might query system metadata on SAS datasets, but the primary objective is the management of a dataset defined by the user or the macro.

1 Code Block

DATA STEP Data

Explanation :
This conditional code block checks for the existence of the target dataset `&libds` using the `%mf_existds` macro. If it does not exist, a DATA step is executed to create the dataset. The `&libds` dataset is defined with specific attributes: a `key` column of 64 characters with a unique index for quick lookups, `valc` of 2048 characters for textual values, `valn` of 8 bytes for numeric values, and `type` of 1 character to indicate the stored value format. `CALL MISSING(OF _ALL_)` initializes all variables to missing values, and `STOP` prevents the DATA step from reading observations, thus creating an empty dataset with the defined structure.

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1	%IF not (%mf_existds(&libds)) %THEN %DO;
2	DATA &libds (index=(key/unique));
3	LENGTH key $64 valc $2048 valn 8 type $1;
4	call missing(of _all_);
5	stop;
6	RUN;
7	%END;

2 Code Block

PROC SQL

Explanation :
This block uses `PROC SQL` to insert or update the key-value pair in the `&libds` dataset. First, a `DELETE` statement is executed to remove any existing row corresponding to the provided `key`, thus ensuring that only one entry exists for each key. Then, an `INSERT` statement is used to add the new key-value pair. The value is stored in the `valc` column if the `type` parameter is 'C' (character), or in `valn` if `type` is 'N' (numeric), using `%SYMGET` or `%SYMGETN` respectively to retrieve the macro variable values. The `type` column is also updated accordingly. `QUIT;` terminates the SQL procedure.

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1	PROC SQL;
2	delete from &libds
3	where key=symget('key');
4	insert into &libds
5	SET key=symget('key')
6	%IF &type=C %THEN %DO;
7	,valc=symget('value')
8	,type='C'
9	%END;
10	%ELSE %DO;
11	,valn=symgetn('value')
12	,type='N'
13	%END;
14	;
15
16	QUIT;

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Copyright Info : Copyright (c) 2001-2006 Rodney Sparapani (pour _version.sas, sous GNU General Public License); Copyright 2010-2023 HMS Analytical Software GmbH (pour macro_without_brief_tag.sas, part of SASUnit, sous GNU Lesser General Public License); Copyright © 2022, SAS Institute Inc. (pour print_macro_parameters.sas, sous SPDX-License-Identifier: Apache-2.0); Copyright (c) 2004 Rodney Sparapani (pour _file.json, sous GNU General Public License); Copyright 2017, Rho, Inc. All rights reserved. (pour list2items.json).

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