Rick and Dan, thanks you taking the time to go through my mail.
I don't know what is a SQL-client module. As per SQL spec Section 4.22SQL-client modules, it is specified using MODULE module-name.... and since Derby does not implement this, I disregarded information on it. I will spend more time looking through the spec to see if I can figure out what it means because literal string are getting their character set (and hence their collation) via SQL-client module when no character set is specified by the string literal. Mamta On 3/26/07, Daniel John Debrunner <[EMAIL PROTECTED]> wrote:
Rick Hillegas wrote: > Hi Mamta, > > Thanks for this extensive write-up. This helps me puzzle through the > issues although I'm afraid I'm still muddled. Some comments follow inline. Same here. > Mamta Satoor wrote: >> lots of good stuff ... +1 > I think we should avoid violating > the SQL standard if we can. +1 In looking at this I was wondering if it would be useful if it could be described in terms of SQL Standard constructs how the system columns come to have a different collation. E.g. is it as though they are declared at the column level with a <collate clause>, or is it as though the system schemas are declared with a different character set to the user schemas? Would this make a difference in how a string literal or other character expressions are collated? For string literals 5.3 SR15) says the collation is the character set collation, and then 5.3 SR14b) says the character set is the the character set of the SQL-client module that contains the <character string literal>. So here's it's unclear to me what 'SQL-client module' means in a derby context. For a function (or any other declared character type except column definitions) the collation will come from its data type, which goes to 6.1 SR3b) and 6.1 SR16), which says implementation defined character set. For a column definition then 11.4 SR10b) specifies the character set as being the schema's character set. Thus Derby could have two character sets: - USER - UCS repertoire with default collation of UCS_BASIC or UNICODE depending on value of collation JDBC attribute at create database time - SYSTEM - UCS repertoire with default collation of UCS_BASIC When a schema is created it is implementation defined as to its character set (if one is not defined) 11.1 SR5) So Derby's implementation could be: user schemas have a character set of USER system schemas have a character set of SYSTEM Then ... - columns would have the required collation (11.4 SR10b)) - functions (& others) would have the required collation (Derby's implementation could be to pick the schema character set) which leaves string literals as the issue, what is a 'SQL-client module'? Dan.
