ODBC Server Reference Manual

Architecture Overview

HP NonStop ODBC Server Reference Manual—429151-002

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NonStop SQL/MP Execution

DATABASE, NOSUTIL creates the NonStop SQL/MP catalog (if it does not already

exist) and customizes it.

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By SCS

SCS maintains one private NOSUTIL process that it uses to process connect

operations and to get configuration information. It passes the connect message to

NOSUTIL, which accesses the NonStop ODBC Server system catalog to map the

server.

NonStop SQL/MP Execution

NonStop SQL/MP execution was originally modeled after the NonStop SQL/MP

conversational interface (SQLCI). The DBLIB model is always execute immediate.

There is no prepare-and-execute paradigm, so only one dynamic NonStop SQL/MP

statement is needed. The remainder of the supplied dynamic statements (about 20)

are available for pass-through commands. The limit of 20 is acceptable for pass-

through commands.

ODBC supports prepare-and-execute operation, so the NonStop ODBC Server needs

a different scheme, as a client can have several concurrently prepared statements. The

NonStop ODBC Server still translates client SQL statements in the original way: it

parses the statements, translates names and literal constants, makes syntax

alterations, and forms a NonStop SQL/MP statement.

To support potentially large numbers of prepared statements, the NonStop ODBC

Server uses the Extended Dynamic SQL of NonStop SQL/MP, whereby statements can

be dynamically allocated and freed (the NonStop ODBC Server can sustain an

arbitrary number of allocated and prepared statements as a function of allocated

memory only. Examples of over 1600 statements have been achieved). For

performance reasons, NonStop SQL/MP is executed directly from the NonStop ODBC

server.