What is host variable?

A host variable is a field in your program that is specified in an SQL statement, usually as the source or target for the value of a column. The host variable and column must have compatible data types.

What is a host variable in Db2?

A host variable is a data item that you declare in a program for use within an SQL statement. You can: Retrieve data into the host variable for your application program's use. Place data into the host variable to insert into a table or to change the contents of a row.

How do you declare host variables?

What is host variable in mainframe?

Host variables are COBOL language variables that are referenced within SQL statements. Host variables allow an application to exchange data with the database manager. After the application is precompiled, host variables are used by the compiler as any other COBOL variable.

What is host variable in pro C?

Host variables are the key to the communication between the host program and the database. A host variable expression must resolve to an lvalue (i.e., it can be assigned). You can declare host variables according to C syntax, as you declare regular C variables.

DB2 - Host Variables

What is pro C used for?

Pro*C (also known as Pro*C/C++) is an embedded SQL programming language used by Oracle Database DBMSes. Pro*C uses either C or C++ as its host language. During compilation, the embedded SQL statements are interpreted by a precompiler and replaced by C or C++ function calls to their respective SQL library.

What is Proc indicator variable?

An indicator variable is a 2-byte integer variable associated with a host language variable in an embedded SQL statement. Indicator variables enable an application to: • Detect when a null value is retrieved. • Assign a null value to a table column, form field, or table field column. • Detect character string ...

What is host variable in PL SQL?

A host variable is a field in your program that is specified in an SQL statement, usually as the source or target for the value of a column. The host variable and column must have compatible data types.

Can host variables be redefined?

You can use the REDEFINES clause when declaring host variables. If you declare a member of a group data item with the REDEFINES clause, and that group data item is referred to as a whole in an SQL statement, any subordinate items containing the REDEFINES clause are not expanded. For example: 01 foo1.

What is cursor in Db2?

Db2 has a mechanism called a cursor . Using a cursor is like keeping your finger on a particular line of text on a printed page. In Db2, an application program uses a cursor to point to one or more rows in a set of rows that are retrieved from a table.

What is Dclgen in Db2?

DCLGEN generates a table or view declaration and puts it into a member of a partitioned data set that you can include in your program. When you use DCLGEN to generate a table declaration, Db2 gets the relevant information from the Db2 catalog.

How are host variables defined in COBOL?

Host variables are data items defined within a COBOL program. They are used to pass values to and receive values from a database. Host variables can be defined in the File Section, Working-Storage Section, Local-Storage Section or Linkage Section of your COBOL program and have any level number between 1 and 48.

Why do we bind in DB2?

The DBRM contains the SQL statements that the DB2 precompiler has extracted from the application program. In the bind process, the SQL statements in the DBRM are put into an operational (“bound”) form, by being translated into the control structures that DB2 uses when it runs SQL statements.

What is foreign key in DB2?

A foreign key is a set of columns in a table which are required to match at least one primary key of a row in another table. It is a referential constraint or referential integrity constraint. It is a logical rule about values in multiple columns in one or more tables.

What is DB in COBOL?

In COBOL, programs interact with DB2 Database. DB2 is Data Base2, which is developed by IBM. It is a Relational Database. The relational data stored in the format of TABLE, which contains Tuples (Rows) and Attributes (Columns).

What is DB2 in mainframe?

Db2 for z/OS is a relational database management system that runs on the mainframe. A relational database is a database in which all of the data is logically contained in tables. These databases are organized according to the relational model.

What is SQLCODE in COBOL?

COBOL programs that contain SQL statements can include an SQL communications area (SQLCA) to check whether an SQL statement executed successfully. Alternatively, these programs can declare individual SQLCODE and SQLSTATE host variables.

What is a bind variable?

Straight from the horse's mouth: “[a] bind variable is a placeholder in a SQL statement that must be replaced with a valid value or value address for the statement to execute successfully. By using bind variables, you can write a SQL statement that accepts inputs or parameters at run time.”

What are the two types of exception in PL SQL?

What are bind parameters?

A parameter binding is a piece of information that is transmitted from the origin to the destination of a flow. A parameter binding has a name and a value, which is obtained at its origin component. A flow may have a multiple parameter binding, passing a set of values instead of a single one.

What is SQL indicator variable?

An indicator variable is a halfword integer variable used to communicate additional information about its associated host variable. If the value for the result column is null, SQL puts a -1 in the indicator variable.

What is embedded SQL in DBMS?

Embedded SQL is a method of combining the computing power of a programming language and the database manipulation capabilities of SQL. Embedded SQL statements are SQL statements written inline with the program source code, of the host language.

How does Proc connect to database?

What is the meaning of || in C?

The logical OR operator ( || ) returns the boolean value true if either or both operands is true and returns false otherwise.

How do you compile a PROC program?

To compile the sample programs in the sample_code/proc directory, you simply run the makefile supplied in the same directory. Note that the appropriate makefile is made available based on the platform of your TimesTen installation. where <program-name> is the program you want to compile.