US 2003/0120636 A1 · Unique identification of SQL cursor occurrences in a repetitive, nested environment

Abstract

A cursor query identifier is defined to uniquely identify cursors in a relational database system that supports nested routine invocation. The identifier includes a cursor nesting level value that corresponds to the nested level at which the cursor is opened. The identifier also includes a invocation identifier that corresponds to the routine within which a cursor is opened. The third part of the identifier is a unique cursor counter. The definition of the cursor query identifier permits cursors to be opened within nested levels of the same relational database context and to be uniquely identified for reference by database system and by applications accessing the system.

Claims22

Dependent claims

A database management system supporting nested invocation of user-defined routines and the definition of cursors, and the system carrying out execution steps in response to requests received from applications and from user-defined routines, the system comprising

means for associating a unique identifier with each cursor occurrence request received by the system, the unique identifier including a first value corresponding to the nesting level of the source process from which the request originated, and a second value uniquely identifying the source process, relative to other sources at the same nesting level;
and
means for passing the unique identifier to the requesting process in response to the cursor occurrence request.

A database management system, the system supporting nested invocation of a set of user-defined routines by an application, and supporting the definition of cursors in applications, the system comprising:

means for defining and maintaining a set of nesting control block data structures, each nesting control block being associated with a unique nesting level of invoked user-defined routines, and comprising a nesting level identifier having a value corresponding to the associated nesting level and containing an invocation counter having a value corresponding to the sequence in which user-defined routines are executed at the associated nesting level,
means for defining and maintaining a set of invocation control block data structures, each invocation control block being associated with a unique invoked user-defined routine, each invocation control block comprising
an invocation control block nesting identifier having a value derived from the nesting level identifier in the nesting control block for the nesting level of the unique invoked user-defined routine,
an invocation identifier having a value derived from the invocation counter in the nesting control block for the nesting level of the unique invoked user-defined routine, and
a cursor counter having a value corresponding to the sequence in which cursors are opened in the unique invoked user-defined routine, means for associating a unique identifier with each cursor occurrence in the execution of a routine invoked by an executing application, the unique identifier comprising
a first value derived from the invocation control block nesting identifier for the invocation control block associated with the executing application,
a second value derived from the invocation identifier for the invocation control block associated with the executing application, and
a third value derived from the cursor counter for the invocation control block associated with the executing application, and means for passing the unique identifier associated with each cursor occurrence to the executing application.

5 more elements

A computer program product for use in a database management system, the system supporting nested invocation of a set of user-defined routines by an application and supporting the definition of cursors, the computer program product comprising a computer usable medium having computer readable code means embodied in said medium for associating a unique identifier with each cursor occurrence in the execution of an executing application, comprising

computer readable program code means for defining a first value in the unique identifier corresponding to the nesting level of the executing application,
computer readable program code means for defining a second value in the unique identifier corresponding to the sequence in which the executing application is invoked by the executing application, relative to other executing applications at the same nesting level, and
computer readable program code means for passing the unique identifier associated with each cursor occurrence to the executing application.

A computer program product for use in a database management system, the system supporting nested invocation of a set of user-defined routines by an application and supporting the definition of cursors in applications, the computer program product comprising a computer usable medium having computer readable code means embodied in said medium for associating a unique identifier with each cursor occurrence in the execution of an executing application, comprising

computer readable program code means for defining and maintaining a set of nesting control block data structures, each nesting control block being associated with a unique nesting level of invoked user-defined routines, and comprising a nesting level identifier having a value corresponding to the associated nesting level and containing an invocation counter having a value corresponding to the sequence in which user-defined routines are executed at the associated nesting level,
computer readable program code means for defining and maintaining a set of invocation control block data structures, each invocation control block being associated with a unique invoked user-defined routine, each invocation control block comprising
an invocation control block nesting identifier having a value derived from the nesting level identifier in the nesting control block for the nesting level of the unique invoked user-defined routine,
an invocation identifier having a value derived from the invocation counter in the nesting control block for the nesting level of the unique invoked user-defined routine, and
a cursor counter having a value corresponding to the sequence in which cursors are opened in the unique invoked user-defined routine,
computer readable program code means for associating a unique identifier with each cursor occurrence in the execution of an executing application, the unique identifier comprising
a first value derived from the invocation control block nesting identifier for the invocation control block associated with the executing application,
a second value derived from the invocation identifier for the invocation control block associated with the executing application, and
a third value derived from the cursor counter for the invocation control block associated with the executing application, and
computer readable program code means for passing the unique identifier associated with each cursor occurrence to the executing application.

7 more elements

A method for defining a set of cursor query identifiers in a database management system, the system supporting nested invocation of a set of user-defined routines by an application, and supporting the definition of cursors in applications, the method comprising:

generating a nesting control block data structure for each unique nesting level of invoked user-defined routines, the nesting control block comprising a nesting level identifier having a value corresponding to the associated nesting level and further comprising an invocation counter having a value corresponding to the sequence in which user-defined routines are executed at the associated nesting level,
generating an invocation control block data structure for each invoked user-defined routine, each invocation control block comprising
an invocation control block nesting identifier having a value derived from the nesting level identifier in the nesting control block for the nesting level of the unique invoked user-defined routine,
an invocation identifier having a value derived from the invocation counter in the nesting control block for the nesting level of the unique invoked user-defined routine, and
a cursor counter having a value corresponding to the sequence in which cursors are opened in the unique invoked user-defined routine, and
defining a unique cursor query identifier in the set of cursor query identifiers for each cursor occurrence in the execution of an executing application, the definition of the unique cursor query identifier further comprising the steps of
deriving a first value component for the cursor query identifier from the invocation control block nesting identifier for the invocation control block associated with the executing application,
deriving a second value component for the cursor query identifier from the invocation identifier for the invocation control block associated with the executing application, and
deriving a third value component for the cursor query identifier from the cursor counter for the invocation control block associated with the executing application.

6 more elements

Dependencies are inferred from the claim text.

Unique identification of SQL cursor occurrences in a repetitive, nested environment

Life of this patent

Unique identification of SQL cursor occurrences in a repetitive, nested environment

Life of this patent

Abstract

Claims22