Hash pointer checking for hierarchical database logical relationship

A method for checking consistency of pointers in a hierarchical database by using a computer including a reading unit, a determination unit, an extraction unit, a calculation unit, and a checking unit, the method comprising:

• reading, by the reading unit, segment information recorded on the hierarchical database;
• determining, by the determination unit, a type of each segment and a type of a pointer included in each segment from the segment information read by the reading unit;
• in accordance with a determination result of the determination unit, extracting, by the extraction unit, from a plurality of child segment, parent pointers pointing to the same parent segment and twin pointers each pointing to the next child segment one after another starting from a specific child segment among the plurality of child segments, and extracting, by the extraction unit, a child pointer from the parent segment, the child pointer pointing to the specific child segment;
• calculating, by the calculation unit, a first hash value by a combination of a storage location address of the parent segment and a value of the child pointer and a combination of the values of the parent pointers and the twin pointers included in the child segments, and a second hash value from a combination of storage location addresses of the child segments and the values of the parent pointers included in the child segments;
• and
• indicating, by the checking unit, a consistency error when the first hash value and the second hash value differ.

A computer program product for checking consistency of pointers in a hierarchical database, the computer program product comprising:

• a computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
• computer readable program code configured for:
• reading segment information recorded on the hierarchical database;
• determining a type of each segment and a type of a pointer included in each segment from the segment information read;
• extracting from a plurality of child segments parent pointers pointing to the same parent segment and twin pointers each pointing to the next child segment one after another starting from a specific child segment among the plurality of child segments, and extracts a child pointer from the parent segment, the child pointer pointing to the specific child segment;
• calculating a first hash value by a combination of a storage location address of the parent segment and a value of the child pointer and a combination of the values of the parent pointers and twin pointers included in the child segments, and a second hash value from a combination of storage location addresses of the child segments and the values of the parent pointers included in the child segments;
• and
• indicating a consistency error when the first hash value and the second hash value differ.