Table of Contents
What is Bldindex used for?
The BLDINDEX command (BIX) is used to build one or more alternate indexes over a base cluster. Both the alternate index and the base cluster must have been previously defined as related to each other by a path, and the base cluster must have been loaded.
How do you populate alternate index?
There are three steps to creating an alternate index.
- Using DEFINE command to create the alternate index.
- Using DEFINE command to create a PATH relating the alternate index to the base cluster.
- Using BLDINDEX command to build the keys for the alternate index.
What is build index in VSAM?
Building Index BLDINDEX command is used to build the alternate index. BLDINDEX reads all the records in the VSAM indexed data set (or base cluster) and extracts the data needed to build the alternate index. BLDINDEX – INDATASET(vsam-cluster-name) – OUTDATASET(alternate-index-name)) Above syntax has two parameters.
What is an alternate index?
An alternate index is a key-sequenced data set containing index entries organized by the alternate keys of its associated base data records. It provides another way of locating records in the data component of a cluster. An alternate index can be defined over a key-sequenced or entry-sequenced cluster.
What is repro in JCL?
The REPRO command performs the following functions: Copies VSAM and non-VSAM data sets. If the data set is a version 2 PDSE with generations, only the current generation of each member is copied. Copies catalogs. Copies or merges tape volume catalogs.
What are VSAM files in Cobol?
VSAM is a file storage access method used in MVS, ZOS and OS/390 operating systems. It was introduced by IBM in 1970’s. It is a high performance access method used to organize data in form of files in Mainframes. VSAM is used by COBOL and CICS in Mainframes to store and retrieve data.
What is alternate index in db2?
Alternate index lets you access the records of a key-sequenced file in a sequence other than that provided by the file’s primary key (or base key). To understand how alternate indexes work, Here, the base cluster (the file over which an alternate index exists) is a KSDS containing employee records.
What is path file in VSAM?
The Define Path screen lets you define a VSAM path and use it to access a VSAM file through an alternate index or access a VSAM file using an alias. To access a VSAM KSDS or VSAM ESDS file through an alternate index, a path must be defined.
What is primary key in VSAM?
You can use the CREATE INDEX statement to define an index that references the columns that make up a VSAM KSDS primary key or the columns that map to an alternate index PATH definition. Indexes identify columns in a table that correspond to a physical index that is in the source database.
What is difference between VSAM and non-VSAM?
Non-VSAM files can be created, edited, and deleted using the ISPF facility. Only works with data stored on disk and can’t handle data stored on other devices like tapes. Files can store on both disks and tapes. VSAM uses its own access method to process the data from files.
What is clustered index in Db2?
A clustering index determines how rows are physically ordered (clustered) in a table space. Clustering indexes provide significant performance advantages in some operations, particularly those that involve many records.
What is Listcat in mainframe?
Summary. The LISTCAT command is used to view dataset attributes, usage statistics, space allocation information, security information, creation and expiration information, etc. LISTCAT command stands for LIST CATalog entry and lists catalog entries.
What is IDCAMS utility?
IDCAMS Utility is very useful utility to manipulate VSAM datasets A typical example of a simple use of IDCAMS is as follows: Example 1: Allocating and Loading Data Into VSAM
What are the possible causes of a failure in IDCAMS define?
A failure can occur with either SMS-managed data sets. A VVDS cannot be modeled in an IDCAMS DEFINE command. Also, SMS forces VVDS defines to be non-SMS-managed, so assignments of EATTR values by either a DATACLAS or a MODEL routine are not allowed with the DEFINE of a VVDS.
Why can’t I model a VVDS in IDCAMS define?
A VVDS cannot be modeled in an IDCAMS DEFINE command. Also, SMS forces VVDS defines to be non-SMS-managed, so assignments of EATTR values by either a DATACLAS or a MODEL routine are not allowed with the DEFINE of a VVDS. The EATTR assignments are only allowed explicitly in the DEFINE CLUSTER command.