Update Lock- This lock allows the program to both read and change the data in the locked area.Įxclusive Lock- This Lock is restricted and does not allow any program to even access the locked space. Shared Lock- This type of lock allows more than one program to read from locked part but not change it. Whenever a primary key is deleted, the foreign key in the corresponding table is also impacted.Ģ0. Tables whose relation is established through a foreign key are called delete-connected tables. It also reduces the requirement of foreign keys.ĭatabase Descriptor or DBD provides restricted access to the database when an object gets created, altered or dropped. What is the benefit of De-normalizing tables in DB 2?ĭenormalizing reduces the necessity of executing various relational joins. STOPRUN stops current work execution to return control to the operating system.ĮXIT PROGRAM is used to quit a program and allow another program to pursue.ġ7. GOBACK gives control back to the calling program. The main differences between GOBACK, STOPRUN and EXIT PROGRAM in COBOL are: What are the differences between GOBACK, STOPRUN and EXIT PROGRAM in COBOL? The composite index is just one index that consists of joint values of 2 columns of the table.ġ6. Multiple indexes consist of 2 indexes, one for each table column. What is the difference between multiple index and composite index? In other words, each foreign key needs to have a primary key.ġ5. Referential integrity rule states that consistency needs to be maintained between primary and foreign keys. The key field of each record is accessed through a randomizer that positions the record in the correct place in the database. Whereas, HDAM does not have a separate index file. This file stores information about the pointer that denotes the position of data. HIDAM has its separate index file based on the root segment. How are HIDAM and HDAM databases different? The three Table spaces are Simple, Segmented and Partitioned Table spaces.ġ3. Type 2 index is quicker than Type 1 index. In Type 1 index, the index pages are locked. In Type 2 index, the data pages get locked but index pages are not locked. Differentiate between Type 1 and Type 2 indexes
SQL code for a deadlock are -911 and -913.ġ1. When two separate processes are fighting for the same resources, or the resource reserved for each other, the situation is called a deadlock. To implement this, the foreign key must define the DELETE CASCADE rule. Self-referencing constraint is used to restrict the changes that can be made to the primary key through a foreign key. What do you mean by self-referencing constraint? Foreign keys are used to build a relation between any two tables.ĩ. The main difference is that INCLUDE is used for expanding at a pre-compiler time whereas COPY is used for expanding at a compiler time.įoreign keys are attributes of a particular table that have matching entries to the primary key in another table.
They are used for extension of design in a program.
INCLUDE and COPY are different in the way they work. We can use the same COPYBOOK for a number of documents using the REPLACING choice if the format is the same.ħ. If a COBOL program needs to speak with a JCL or another program through the PARM parameter, Linkage Area is used.ĬOPYBOOK stores the format of any record and uses the same design for another program. Explain the function of Linkage Area in COBOL Runstats is used to clear the default values of these columns.ĥ. The catalog columns are filled with default values and the end result during environment testing may not produce accurate results. How is runstats used in environment testing? These tables are needed during the testing phase of the production environment.Ĥ. You can use the LIKE parameter and the CREATE statement to create the LIKE table. Explain how the LIKE table can be created? While working with a relational database system, the clause “WHERE” isolates an element or a row.ģ. What is the function of the clause WHERE in mainframe programming? This architecture contains a set of rules that helps communicate between any application and database relation.Ģ. It works as a connection protocol for local database processing. Below are the top 20 Mainframe interview questions that are most commonly asked in Mainframe interview.ĭRDA stands for Distributed Relational Database Architecture. If you are here looking for help to prepare for your next Mainframe interview, you are at the right place. If you are looking to advance your career as a Mainframe Developer, opportunities are numerous.