Firebird experience summary

Recently, I am rewriting a paragraph ms sql Stored procedure to firebird, Sum up some experience , firebird It can be said to be the smallest database in the world that supports stored procedures , only 2.3M nothing more , If you do small applications , Than ms sql Desktop version is also available 70 many M（+sp3）, mysql Also have 20-30M, It's too inconvenient .

1. Custom function problem .Access to UDF library “rfunc.dll” is denied by server administrator It took a long time , I don't understand why , take rfunc.dll Kao to udf Catalog ,bin Catalog ,windows\system32 Directories can't solve the problem ,google once , There are the same problems online , But there is no solution , As a result, I reinstalled firebird It's settled. .

2. Definition of variables in stored procedures ms sql New variables can be defined anywhere in the stored procedure , But in firebird in , Only in as And begin Between .firebird The variable of cannot be used @ Symbol , I will @ All become a Just fine .

3. Use of variables in stored procedures select @i=count(*) from table1 //ms sqlselect count(*) from table1 into :i//firebird Reference variables use colons 4. The embedded sql, firebird Support select * from table exists (select …) or select * from table in (select …) But does not support select * from (select * from …) a, I solve this problem by rewriting it as a view

5.case sentence mssql You can use field= case (), but firebbird Support only case () as field, 6.mssql getdate() become CURRENT_DATE+CURRENT_TIME select * from snartleave where dt_starttime<CURRENT_DATE+CURRENT_TIME or select * from snartleave where dt_starttime<CURRENT_DATE||’ ‘ ||CURRENT_TIME

7. Write the stored procedure of the returned data set (firebird It's a bit troublesome to write ) CREATE PROCEDURE SPVARTST2 ( VAR_IPTARTNO CHAR(6))RETURNS ( VAR_ARTNAME CHAR(10))ASbeginfor select v_name1 from snart where v_artNo=:var_iptartno into :var_artname dosuspend;end

8. Use of automatic growth fields (autoincrement) firebird There is a generator (generator) The east east , Record the increase of the value in the generator , Then use trigger to realize beginif (new.i_seqno is null) thenbegin NEW.i_seqno = GEN_ID(GEN_T_DB_ARTSEQNO_ID,1);endend //GEN_T_DB_ARTSEQNO_ID Is the generator created , See no , In other words, different tables and fields can share a generator ,gen_id amount to identity, Looks like mssql complex , It's also very simple .

9. Generator reset 　mssql It seems troublesome to reset the automatically added fields in , More difficult to control , firebird It can be like this ( Stored procedure ) agenerator=Gen_ID(GEN_T_DB_ARTSEQNO_ID,Gen_ID(GEN_T_DB_ARTSEQNO_ID,0)*-1+1); //agenerator It's a plastic variable , It seems that you must pretend gen_id The value symbol of is given to a variable , I don't know if there's a better way , Don't define an extra variable Please refer to the following website ：http://www.fingerbird.de/generatorguide_body.htm

10 Change the data of another table through one table mssql:update table1 set cname=b.cname from table1 a inner join table2 as b where a.id=b.id firebird:update table1 a set cname=(select cname from table 2 b where b where a.id=b.id) 11. How to select the first few records mssql: select top 10 * from table1 firebird:select first 10 * from table1 IB:select * from table rows 10 12.Firebird Storing transactions in stored procedures In stored procedures ib/fb Starting or ending a transaction is not supported . The submission is submitted by the caller . That is to say ,fb/ib Stored procedures should be designed in a transaction . stay sql server in , Stored procedures or such transactions ： begin trancstion commit trancstion But in fb/ib There is no such thing in You need to start a transaction in the transferred program Such as : pFIBDtbsMain.StartTransaction; pFIBDtbsMain.Commit;

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