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CNTLLEV=

Valid in:	DATA step and PROC steps
Category:	Data Set Control
Restriction:	Specify for input data sets only.

Syntax Description

LIB

controls concurrent access at the library level. Library-level control restricts concurrent access to only one update process to the library.

MEM

controls concurrent access at the SAS data set (or member) level. Member-level control restricts concurrent access to only one update or output process but allows read access to many sessions, procedures, or statements.

REC

controls concurrent access at the observation (or record) level. Record-level control allows more than one update access to the same SAS data set, but it denies concurrent update of the same observation.

Details

The CNTLLEV= option specifies the level at which shared update access to a SAS data set is denied. A SAS data set can be opened concurrently by more than one SAS session or by more than one statement, window, or procedure within a single session. By default, SAS procedures permit the greatest degree of concurrent access possible while they guarantee the integrity of the data and the data analysis. Therefore, you do not normally use the CNTLLEV= option.

Use this option when

• your application controls the access to the data, such as in SAS Component Language (SCL), SAS/IML software, or DATA step programming

• you access data through an interface engine that does not provide member-level control of the data.

If you use CNTLLEV=REC and the SAS procedure needs member-level control for integrity of the data analysis, SAS prints a warning to the SAS log that inaccurate or unpredictable results can occur if the data are updated by another process during the analysis.

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