Question

I’ve got a T-SQL script, that converts field to IDENTITY (in a weird way).

How do I convert it to PL/SQL? (and, probably, figure out, if there is a simpler way to do this – without creating a temporary table).

The T-SQL script:

-- alter table ts_changes add TS_THREADID VARCHAR(100) NULL;

-- Change Field TS_ID TS_NOTIFICATIONEVENTS to IDENTITY
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_TS_NOTIFICATIONEVENTS
    (
    TS_ID int NOT NULL IDENTITY (1, 1),
    TS_TABLEID int NOT NULL,
    TS_CASEID int NULL,
    TS_WORKFLOWID int NULL,
    TS_NOTIFICATIONID int NULL,
    TS_PRIORITY int NULL,
    TS_STARTDATE int NULL,
    TS_TIME int NULL,
    TS_WAITSTATUS int NULL,
    TS_RECIPIENTID int NULL,
    TS_LASTCHANGEDATE int NULL,
    TS_ELAPSEDCYCLES int NULL
    )  ON [PRIMARY]

SET IDENTITY_INSERT dbo.Tmp_TS_NOTIFICATIONEVENTS ON
GO
IF EXISTS(SELECT * FROM dbo.TS_NOTIFICATIONEVENTS)
     EXEC('INSERT INTO dbo.Tmp_TS_NOTIFICATIONEVENTS (TS_ID, TS_TABLEID, TS_CASEID,    TS_WORKFLOWID, TS_NOTIFICATIONID, TS_PRIORITY, TS_STARTDATE, TS_TIME, TS_WAITSTATUS, TS_RECIPIENTID, TS_LASTCHANGEDATE, TS_ELAPSEDCYCLES)
    SELECT TS_ID, TS_TABLEID, TS_CASEID, TS_WORKFLOWID, TS_NOTIFICATIONID, TS_PRIORITY, TS_STARTDATE, TS_TIME, TS_WAITSTATUS, TS_RECIPIENTID, TS_LASTCHANGEDATE, TS_ELAPSEDCYCLES FROM dbo.TS_NOTIFICATIONEVENTS WITH (HOLDLOCK TABLOCKX)')
GO
SET IDENTITY_INSERT dbo.Tmp_TS_NOTIFICATIONEVENTS OFF
GO
DROP TABLE dbo.TS_NOTIFICATIONEVENTS
GO
EXECUTE sp_rename N'dbo.Tmp_TS_NOTIFICATIONEVENTS', N'TS_NOTIFICATIONEVENTS', 'OBJECT' 
GO
ALTER TABLE dbo.TS_NOTIFICATIONEVENTS ADD CONSTRAINT
aaaaaTS_NOTIFICATIONEVENTS_PK PRIMARY KEY NONCLUSTERED 
(
TS_ID
) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

GO
COMMIT

Answer 1

From version 12C, Oracle supports the IDENTITY data type e.g.:

CREATE TABLE Tmp_TS_NOTIFICATIONEVENTS
    ( TS_ID int NOT NULL GENERATED ALWAYS AS IDENTITY.
    ...

Prior to version 12C, Oracle doesn’t have an IDENTITY data type, so there is no equivalent PL/SQL code for this. If you want to ensure that all future inserts automatically get assigned a unique value for TS_ID you can do this:

1) Find out the highest value currently used:

select max(ts_id) from TS_NOTIFICATIONEVENTS;

2) Create a sequence that starts with a value higher than that, e.g.:

create sequence ts_id_seq start with 100000;

3) Create a trigger to populate the column from the sequence on insert:

create or replace trigger ts_id_trig
before insert on TS_NOTIFICATIONEVENTS
for each row
begin
    :new.ts_id := ts_id_seq.nextval;
    -- or if pre 11G:
    -- select ts_id_seq.nextval into :new.ts_id from dual;
end;