Posted by jpluimers on 2022/10/27
I knew there was JSFiddle for live playing around with JavaScript and more in your browser, so I wondered if there was a similar site for databases and SQL queries.
There are, so here are a few database fiddle sites: SQL playgrounds where you can live play with SQL queries (sometimes even without an underlying example database).
All via [Wayback/Archive.is] database fiddle – Google Search:
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Posted by jpluimers on 2021/07/08
For my link archive:
–jeroen
Posted in Database Development, Delphi, Development, Firebird, Software Development | Leave a Comment »
Posted by jpluimers on 2020/09/17
Though the field-types mentioned in the problem and solution are equal (so either is wrong), the solution in [WayBack] I have a little problem with FireDAC and the TStringField and TWideStringField design time generation… – Juan C. Cilleruelo – Google+ pointed out by Jeff Weir is interesting: FireDAC supports conditionals that depend on the DBMS back-end, so you can differentiate between them.
The feature is called Conditional Substitution and has been present ever since AnyDAC (which got bought by Embarcadero, transformed into FireDAC, then after Idera bought Embarcadero, the main developer got pink-slipped).
The AnyDAC documentation is in the wayback machine, though you have to disable the onload event in order to read it.
The [Archive.is] XE5: Preprocessing Command Text (FireDAC) – RAD Studio documentation is not much different from the current state [Archive.is].
More background reading is at [WayBack] www.freepascal.org/~michael/articles/anydac2/anydac2.pdf and Cary Jensen covered it in his 2017 course on FireDAC of which you can see the free ToC.
Example from that thread:
SELECT ART.CD_ITEM ,
ART.CD_FAMILY ,
ART.CD_CATALOGUE ,
CAT.DS_CATALOGUE ,
FAM.DS_FAMILY ,
{IF MSSQL}
CASE WHEN EXISTS(SELECT 1 FROM CONFIGURATIONS COM WHERE COM.CD_PARENT = ART.CD_ITEM)
THEN CAST('Y' AS NVARCHAR)
ELSE CAST('N' AS NVARCHAR)
END HAS_CONFIGURATION ,
{fi}
{IF FIREBIRD}
CASE WHEN EXISTS(SELECT 1 FROM CONFIGURATIONS COM WHERE COM.CD_PARENT = ART.CD_ITEM)
THEN 'Y'
ELSE 'N'
END HAS_CONFIGURATION ,
{fi}
ART.DS_ITEM ,
ART.CD_TAX ,
TAX.DS_TAX ,
TAX.PRC_TAX ,
...
Given the problem statement, the casts likely should have been VARCHAR instead of NVARCHAR, but the construct can be very powerful.
–jeroen
Posted in Database Development, Delphi, Development, Firebird, InterBase, Software Development, SQL, SQL Server | Leave a Comment »
Posted by jpluimers on 2019/09/11
The RDB$RELATIONS.RDB$RELATION_TYPE was introduced in Firebird 2.1 with these enumeration values:
enum rel_t {
rel_persistent = 0,
rel_view = 1,
rel_external = 2,
rel_virtual = 3,
rel_global_temp_preserve = 4,
rel_global_temp_delete = 5
};
You should access it assuming NULL means zero (0), so you better treat it using [WayBack] COALESCE() like COALESCE(RDB$RELATIONS.RDB$RELATION_TYPE, 0).
Background information:
RDB$RELATIONS.RDB$RELATION TYPE–jeroen
Posted in Database Development, Development, Firebird | Leave a Comment »
Posted by jpluimers on 2019/09/05
Since I likely need these [WayBack] SQL Language Changes in the future (some breaking Firebird 2.x habits).
The odd thing is that I got there looking for “no column name specified for column number 1 in derived table” when doing some weird CTE query things in Firebird 2.5x
–jeroen
Posted in Database Development, Development, Firebird | Leave a Comment »
The Wiert Corner - irregular stream of stuff 