# US 2010/0169307 A1 · Performing an efficient implicit join of multiple mixed-type records

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- Number: US 2010/0169307 A1
- Document ID: US20100169307A1
- Status: Published application
- Kind: A1
- Application number: 12/345,663
- Filed: 2008-12-30
- Published: 2010-07-01
- Earliest claimed: 2008-12-30
- Assignees: International Business Machines Corporation
- Inventors: Shawfu Chen; Adris E. Hoyos; Kevin T. Jones; Bernard Klos; Aleksandr Krymer
- Web page: https://patentgrep.com/patent/US20100169307A1

## CPC

- G06F 16/217: {Database tuning (G06F16/2282 takes precedence; database performance monitoring G06F11/3409)}
- Y10S 707/956: Hierarchical
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method, system, method and computer program product for retrieving data. Records are retrieved from a hierarchical database. The records are categorized into a plurality of record types. Each record comprises a unique identifier field. A record map contains zero or more entries. Each entry comprises an identifying value, data from at least one record and a set of Boolean flags. Each flag corresponds to a record type. A computer iterates over the retrieved records. Data from each record is stored at an entry in the record map having an identifying value equal to the value included in the unique identifier field of the record. Moreover, the flag in this entry which corresponds to the record type of the record is set. Inner joins and outer joins are then performed using the contents of the record map.

## Claims

### Claim 1

A method for retrieving data, the method comprising:
retrieving a plurality of records from a hierarchical database, the plurality of records categorized into a plurality of record types, each record included in the plurality of records comprising a unique identifier field;
iterating over each record included in the retrieved plurality of records, wherein iterating over each record is performed at a computer;
for each record for which a value contained in the unique identifier field is not included in a record map, creating an entry in the record map, the created entry comprising the value contained in the unique identifier field, a subset of the record and a set of flags, each flag included in the set of flags corresponding to a record type, wherein each flag included in the set of flags is set to a first Boolean value if the record is of the type corresponding to the flag and a second Boolean value if the record is not of the type corresponding to the flag; and
for each record for which the value contained in the unique identifier field is included in an existing entry in the record map, adding a subset of the record to the existing entry and setting the flag included in the existing entry and corresponding to the record type of the record to the first Boolean value.

### Claim 2 (depends on 1)

The method of claim 1, further comprising performing an inner join, wherein performing the inner join comprises outputting the subsets of records included in each entry in the record map for which all flags included in the set of flags contain the first Boolean value.

### Claim 3 (depends on 1)

The method of claim 1, further comprising performing an outer join, wherein performing the outer join comprises outputting the subsets of records included in each entry in the record map for which at least one flag included in the set of flags contains the first Boolean value.

### Claim 4 (depends on 1)

The method of claim 1, further comprising filtering the plurality of records to include only records matching at least one criterion specified by a query, wherein filtering the plurality of records is performed before iterating over each record included in the retrieved plurality of records.

### Claim 5 (depends on 1)

The method of claim 1, wherein the plurality of records is included in a single subfile included in the database.

### Claim 6 (depends on 1)

The method of claim 1, wherein a query is processed using a single pass through the database.

### Claim 7 (depends on 1)

The method of claim 1, further comprising analyzing metadata about the plurality of records to determine a location of the unique identifier field.

### Claim 8 (depends on 7)

The method of claim 7, wherein the metadata is expressed using Extensible Markup Language (XML).

### Claim 9

A system for retrieving data, the system comprising:
a retrieving unit configured to retrieve a plurality of records from a hierarchical database, the plurality of records categorized into a plurality of record types, each record included in the plurality of records comprising a unique identifier field;
a record map, the record map containing zero or more entries, wherein each entry stored at the record map comprises an identifying value, a subset of at least one record and a set of flags, each flag included in the set of flags corresponding to a record type; and
a processor configured to:
iterate over each record included in the plurality of records retrieved by the retrieving unit;
for each record for which a value contained in the unique identifier field is not included in a record map, create an entry in the record map, the created entry comprising the value contained in the unique identifier field, a subset of the record and a set of flags, each flag included in the set of flags corresponding to a record type, wherein each flag included in the set of flags is set to a first Boolean value if the record is of the type corresponding to the flag and a second Boolean value if the record is not of the type corresponding to the flag; and
for each record for which the value contained in the unique identifier field is included in an existing entry in the record map, add a subset of the record to the existing entry and set the flag included in the existing entry and corresponding to the record type of the record to the first Boolean value.

### Claim 10 (depends on 9)

The system of claim 9, further comprising a joining unit configured to perform an inner join, wherein performing the inner join comprises outputting the subsets of records included in each entry in the record map for which all flags included in the set of flags contain the first Boolean value.

### Claim 11 (depends on 9)

The system of claim 9, further comprising a joining unit configured to perform an outer join, wherein performing the outer join comprises outputting the subsets of records included in each entry in the record map for which at least one flag included in the set of flags contains the first Boolean value.

### Claim 12 (depends on 9)

The system of claim 9, further comprising a filtering unit configured to filter the plurality of records to include only records matching at least one criterion specified by a query, wherein filtering the plurality of records is performed before iterating over each record included in the retrieved plurality of records.

### Claim 13 (depends on 9)

The system of claim 9, wherein the plurality of records is included in a single subfile included in the database.

### Claim 14 (depends on 9)

The system of claim 9, wherein a query is processed using a single pass through the database.

### Claim 15 (depends on 9)

The system of claim 9, further comprising an analyzing unit configured to analyze metadata about the plurality of records to determine a location of the unique identifier field.

### Claim 16

A computer program product embodied in a computer usable memory comprising:
computer readable program codes coupled to the computer usable memory for retrieving data, the computer readable program codes configured to cause the program to:
retrieve a plurality of records from a hierarchical database, the plurality of records categorized into a plurality of record types, each record included in the plurality of records comprising a unique identifier field;
iterate over each record included in the retrieved plurality of records;
for each record for which a value contained in the unique identifier field is not included in a record map, create an entry in the record map, the created entry comprising the value contained in the unique identifier field, a subset of the record and a set of flags, each flag included in the set of flags corresponding to a record type, wherein each flag included in the set of flags is set to a first Boolean value if the record is of the type corresponding to the flag and a second Boolean value if the record is not of the type corresponding to the flag; and
for each record for which the value contained in the unique identifier field is included in an existing entry in the record map, add a subset of the record to the existing entry and set the flag included in the existing entry and corresponding to the record type of the record to the first Boolean value.

### Claim 17 (depends on 16)

The computer program product of claim 16, wherein the computer readable program codes are further configured to cause the program to perform an inner join, wherein performing the inner join comprises outputting the subsets of records included in each entry in the record map for which all flags included in the set of flags contain the first Boolean value.

### Claim 18 (depends on 16)

The computer program product of claim 16, wherein the computer readable program codes are further configured to cause the program to perform an outer join, wherein performing the outer join comprises outputting the subsets of records included in each entry in the record map for which at least one flag included in the set of flags contains the first Boolean value.

### Claim 19 (depends on 16)

The computer program product of claim 16, wherein the computer readable program codes are further configured to cause the program to filter the plurality of records to include only records matching at least one criterion specified by a query, wherein filtering the plurality of records is performed before iterating over each record included in the retrieved plurality of records.

### Claim 20 (depends on 16)

The computer program product of claim 16, wherein a query is processed using a single pass through the database.