Managing VARCHAR data in CAS

Attention : This code requires administrator privileges.

The script initializes a CAS session and configures the CASLIBs. It then creates a temporary SAS^© table (`saswork_table_with_char300`) with character variables of 300, 15, and 16 bytes respectively. After examining its structure via PROC CONTENTS, it manipulates a `sas^©7bdat` CASLIB to point to the SAS^© `WORK` directory. Finally, it loads the created table into CAS using `PROC CASUTIL` with the `varcharconversion=16` option to manage character variables, then displays the column information of the loaded table in CAS. CASLIB manipulations (`_all_ assign`, `dropCaslib`, `addcaslib`) are administration-level actions.

Data Analysis

Type : CREATION_INTERNE

The `saswork_table_with_char300` table is created directly in the script via a DATA step with implicit `datalines`.

1 Code Block

CAS Session Management

Explanation :
This block initializes a CAS session, assigns all available CASLIBs to the session, and defines a macro variable `workpath` containing the path to the SAS WORK directory. This is essential for managing data between SAS and CAS. The assignment of `caslib _all_` is an administrative action.

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1	/*
2	Copyright © 2021, SAS Institute Inc., Cary, NC, USA. All Rights Reserved.
3	SPDX-License-Identifier: Apache-2.0
4	*/
5	/* cas casauto terminate; */
6	cas;
7	caslib _all_ assign;
8
9	/* WORKPATH contains the path to SASWORK */
10	%let workpath = %sysfunc(quote(%sysfunc(pathname(work)))) ;
11	%put &workpath;

2 Code Block

DATA STEP Data

Explanation :
This DATA step creates the temporary `saswork_table_with_char300` table in the WORK library. It defines three character variables (`a`, `b`, `c`) with initial lengths of 300, 15, and 16 bytes respectively, then inserts three observations. This table will be used to demonstrate VARCHAR conversion in CAS.

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1	DATA saswork_table_with_char300;
2	LENGTH a $ 300 b $ 15 c $ 16;
3	a='a300'; b='b15' ; c='c16' ;
4	OUTPUT;
5	a='a300300'; b='b151515'; c='c161616';
6	OUTPUT;
7	c='c161616161616161';
8	b='b15151515151515';
9	a="a300qzwsxedcrfvtgbyhnujmiklopqazwsxedcrfvtgbyhnujmikolp1234567890123456789012345678901234567890";
10	OUTPUT;
11	RUN;

3 Code Block

PROC CONTENTS

Explanation :
This procedure displays the metadata of the `saswork_table_with_char300` table, including variable names, types, and lengths. This allows verifying the structure of the SAS table before its transfer to CAS and confirming the lengths of the character variables.

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1
2	PROC CONTENTS
3	DATA=saswork_table_with_char300;
4	title "Contents of WORK.SASWORK_TABLE_WITH_CHAR300";
5	RUN;
6

4 Code Block

PROC CAS (CASLIB Management)

Explanation :
This block uses `PROC CAS` to manage a CASLIB named `sas7bdat`. It first attempts to delete this CASLIB if it already exists (`dropCaslib`), then recreates it (`addcaslib`) by pointing it to the SAS WORK directory path (`&workpath`). This step is necessary for CAS to access SAS files stored in the WORK directory. Direct manipulation of CASLIBs is an administrative action.

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1	PROC CAS;
2	file log;
3	TABLE.dropCaslib /
4	caslib='sas7bdat' quiet = true;
5	RUN;
6	addcaslib /
7	datasource={srctype="path"}
8	name="sas7bdat"
9	path=&workpath ;
10	RUN;

5 Code Block

PROC CASUTIL Data

Explanation :
This procedure loads the `saswork_table_with_char300` table (which is saved on disk in the WORK directory as `saswork_table_with_char300.sas7bdat`) into the CAS server under the name `cas_table_with_varchar` in the `casuser` CASLIB. The `varcharconversion=16` option is crucial here: it forces SAS character variables with a length greater than 16 bytes to be converted to VARCHAR type in CAS, allowing for more efficient storage of variable-length character strings and optimizing memory usage in CAS.

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1	PROC CASUTIL;
2	load casdata="saswork_table_with_char300.sas7bdat"
3	casout="cas_table_with_varchar"
4	outcaslib="casuser"
5	importoptions=(filetype="basesas", dtm="auto", debug="dmsglvli", varcharconversion=16) ;
6	RUN;
7	QUIT;
8
9	title;

6 Code Block

PROC CAS (Table Inspection)

Explanation :
This last block uses `PROC CAS` to set session options on the `casuser` CASLIB, then calls the CAS action `table.columninfo` to display detailed column metadata for the `cas_table_with_varchar` CAS table. This allows verifying how character variables were handled after VARCHAR conversion, particularly confirming that variables 'a' and 'c' were converted to VARCHAR.

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1	PROC CAS;
2	sessionProp.setSessOpt /
3	caslib="casuser";
4	RUN;
5	TABLE.columninfo / TABLE="cas_table_with_varchar";
6	QUIT;

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