Introduction to ESDS

Record storage in an Entry-Sequenced Data Set (ESDS) is determined by the order in which the records are entered into the data set without respect to the record contents. New records are stored at the end of the data set. An ESDS is appropriate for applications that do not require any particular ordering of the data by the record contents or for those that require time-ordered data. Applications that use a log or journal are well suited for an ESDS data set structure.

The options associated with reading, adding, and updating ESDS records are described in the following sections. In many cases, the option's meaning depends on how it is used within a SAS program. (Loading ESDS records is discussed separately in Defining and Loading a VSAM Data Set.)

The following are three helpful tables and their descriptions:

SAS Options for an ESDS lists the options that are significant for processing ESDS records.
Access Types for ESDS Operations summarizes the access type that you can use for each ESDS operation.
Operations on an ESDS with an Alternate Index points out the type of access that you can use for an ESDS with an alternate index.

Finally, there are examples of reading, adding, updating, and performing combined operations on an ESDS data set. The examples are based on the data set described inSample STUDENT Data Set.

For information about using a KSDS in SAS jobs, see Processing a KSDS in a SAS Job. For information about using an RRDS in SAS jobs, see Processing an RRDS in a SAS Job.