Generating and Compiling › Implementing › Identifying the Implementation Attributes

Identifying the Implementation Attributes

The following table shows the i OS implementation attributes for each of the access paths:

The following legend applies for the access path types:

(1) Unique key status (DDS unique keyword or SQL unique keyword with create index statement). U indicates unique; if not unique, see Note (2). The default UPD and RTV access paths must be unique.

(2) Duplicate key sequence for DDS only (L=LIFO, F=FIFO,' '=undefined, C=FCFO).

(3) i OS access path maintenance (I=*IMMED,R=*REBLD, D=*DLY). For QRY access paths, see item (6).

(4) Alternative collating sequence table for DDS only (DDS ALTCOL keyword).

(5) Selection type (S=static, D=dynamic) (DDS DYNSLT keyword).

(6) Causes the i OS OPNQRYF command to be called with the OPTIMIZE option equal to *FIRSTIO, *MINWAIT, or *ALLIO, respectively.

For SQL, static selection is implemented through SQL Data Definition Language (DDL) statements. Dynamic selection is implemented by Data Manipulation Language (DML) statements.

Note: If an SQL-generated RSQ access path has select/omit criteria and is defined as Unique with Static maintenance, the key defined as unique must be unique over the entire file and not just with a subset of that file (as defined by the select/omit criteria).

The current implementation of the DDL generation mode is not valid for SPN access path, QRY access path, access paths that have virtual fields, and multi-member files.

In addition, the following table shows which of the SPN access path / QRY access path / access paths that have virtual fields / multi-member files are valid for SQL implementation.