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1SQL - Concurrent insert of keys into a table
2except
3  on E: EIBInterBaseError do
4  begin
5    if (E.SQLCode = -803) and (E.IBErrorCode = 335544349) then
6    begin
7      FKeysConnection.IBT.Rollback;
8      EnteredKeys := False;
9    end;
10  end;
11end;
12	
13except
14  on E: EIBInterBaseError do
15  begin
16    if (E.SQLCode = -803) and (E.IBErrorCode = 335544349) then
17    begin
18      FKeysConnection.IBT.Rollback;
19      EnteredKeys := False;
20    end;
21  end;
22end;
23	
24UPDATE OR INSERT INTO MY_TABLE (MY_KEY) VALUES (:MY_KEY) MATCHING (MY_KEY) RETURNING MY_ID
25	
26insert into Table1 (KeyValue) 
27select 'NewKey'
28where not exists (select *
29                  from Table1
30                  where KeyValue = 'NewKey')
31	
32CREATE TABLE KEY_RESERVATIONS (
33  KEY INTEGER NOT NULL, /* This is the KEY you'd be reserving */
34  RESERVED_UNTIL TIMESTAMP NOT NULL /* We don't want to keep reservations for ever in case of failure */
35);