Ocelot's Conformance To The Full SQL-92 Standard

A claim of "full SQL-92 conformance" implies several things. Some of them are legalese or technical, so disclaimers and explanations are appropriate.

To begin with: SQL-92 (or SQL/92 or SQL'92 or however you like) is the pre-1999 formal standard for SQL as set out in a document published by the American National Standards Institute in 1992. There are three conformance levels: "entry" (a small subset which is nearly equivalent to the previous "SQL-89" Standard), "intermediate" (we believe that Oracle and Sybase may be at this level but we are not familiar with other databases so check with the vendors of those products before taking our word for it), and "full". Typically, an intermediate product will lack most or all of these features: creatable character sets, creatable collations, scalar subqueries, except+intersect, bit+interval datatypes, a schema named information_schema, multiple catalogs, case+cast functions, deferrable constraints, domains ... check your old DBMS to see which of these features is missing. THE OCELOT SQL DBMS has all those features, so we claim to be at the full level.

What does "claim" mean? Well, we can't produce a certificate and we can't cite any independent authority to back this up. In fact we don't even say that every little thing will work, for two reasons: (a) there are some details in the ISO/ANSI Standard document which are incomprehensible or which, if really implemented, would cripple the end user's application, and (b) our support is strictly for "direct SQL" and therefore does not include the verbs such as ALLOCATE/DEALLOCATE which are relevant for module SQL only. What we do mean by "claim" is: THE OCELOT SQL DBMS should work as described in the SQL-92 document.

The SQL Standard has many "implementor-defined" items -- that is, cases where the vendor is allowed to make its own decision about syntax or behaviour. It cannot be expected that two different vendors will make the same decisions, so full SQL-92 compatibility does not necesarily imply compatibility with other vendors' products. There are several implementor-defined issues which we deal with in the full documentation. Also, there are two objects -- indexes and triggers -- which are common in other DBMS implementations but are not SQL-92 and are therefore not fully supported by THE OCELOT SQL DBMS

Finally, SQL-92 was superseded by SQL-99 (or SQL3) in 1999. SQL-99 will soon be superseded too, by SQL:2003. Our most recent work on THE OCELOT SQL DBMS was towards SQL-99 compliance. Thus, our package also has limited support (sometimes very limited) for CREATE FUNCTION, CREATE PROCEDURE, BOOLEAN data type, CREATE ROLE, DROP ROLE, ARRAY, compound statements, IF ELSE END IF, LOOP END LOOP, ITERATE, CALL, LEAVE, WHILE, REPEAT, delete triggers, CLOBs, BLOBs, and SIMILAR predicates.

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