I have a table
CREATE TABLE STUDENT
(
ID INTEGER PRIMARY KEY,
FIRSTNAME VARCHAR2(1024 CHAR),
LASTNAME VARCHAR2(1024 CHAR),
MODIFIEDDATE DATE DEFAULT sysdate
)
I am inserting a row of data
insert into STUDENT (ID, FIRSTNAME, LASTNAME, MODIFIEDDATE) values (1,'Scott', 'Tiger', sysdate);
When I have to insert a record of data, I need to write a procedure or function which does the following:
if there is no record for the same id insert the row.
if there is a record for the same id and data matches then do nothing.
if there is a record for the same id but data does not match then update the data.
I am new to oracle. From the java end, It is possible to select the record by id and then update that record, but that would make 2 database calls. just to avoid that I am trying update the table using a procedure. If the same can be done in a single database call please mention.
For a single SQL statement solution, you can try to use the MERGE statement, as described in this answer https://stackoverflow.com/a/237328/176569
e.g.
create or replace procedure insert_or_update_student(
p_id number, p_firstname varchar2, p_lastname varchar2
) as
begin
merge into student st using dual on (id = p_id)
when not matched then insert (id, firstname, lastname)
values (p_id, p_firstname, p_lastname)
when matched then update set
firstname = p_firstname, lastname = p_lastname, modifiedate = SYSDATE
end insert_or_update_student;
instead of procedure try using merge in oracle .
If Values is matched it will update the table and if values is not found it will insert the values
MERGE INTO bonuses b
USING (
SELECT employee_id, salary, dept_no
FROM employee
WHERE dept_no =20) e
ON (b.employee_id = e.employee_id)
WHEN MATCHED THEN
UPDATE SET b.bonus = e.salary * 0.1
DELETE WHERE (e.salary < 40000)
WHEN NOT MATCHED THEN
INSERT (b.employee_id, b.bonus)
VALUES (e.employee_id, e.salary * 0.05)
WHERE (e.salary > 40000)
Try this
To solve the second task - "if there is a record for the same id and data matches then do nothing." - starting with 10g we have additional "where" clause in update and insert sections of merge operator.
To do the task we can add some checks for data changes:
when matched then update
set student.last_name = query.last_name
where student.last_name <> query.last_name
This will update only matched rows, and only for rows where data were changed
Related
I need to write PL/SQL procedure with cursor for loop to insert/update the data rowwise.
Data from staging table needs to be populated to main table.
It will first check if the project_id and department exist or not in main table,then it will insert/update accordingly.
(Merge cannot be used as per requirement)
So i have staging table which gets populated.
STAGE_PROJECT
So, if the project_id,department exist,contract and scope columns would get updated.
Else the row would get inserted.
Destination table:
PROJECT_DATA
Example: for ERP and SAP, contract and scope would get updated and for DWH,since the project_id and department do not exists, row will get inserted .
Hopes this helps
I created your tables.
CREATE TABLE STAGE_PROJECT
(
PROJECT_ID NUMBER,
DEPARTMENT VARCHAR2(30),
CONTRACT VARCHAR2(30),
"SCOPE" VARCHAR2(30),
FINAL_DATE DATE
);
CREATE TABLE PROJECT_DATA
(
PROJECT_ID NUMBER,
DEPARTMENT VARCHAR2(30),
CONTRACT VARCHAR2(30),
"SCOPE" VARCHAR2(30),
FINAL_DATE DATE
);
And inserted your data.
INSERT INTO PROJECT_DATA(PROJECT_ID, DEPARTMENT) VALUES (1 , 'ERP');
INSERT INTO PROJECT_DATA(PROJECT_ID, DEPARTMENT) VALUES (2 , 'SAP');
INSERT INTO STAGE_PROJECT(PROJECT_ID, DEPARTMENT, CONTRACT, SCOPE) VALUES (1 , 'ERP', 'NEW','FINAL');
INSERT INTO STAGE_PROJECT(PROJECT_ID, DEPARTMENT, CONTRACT, SCOPE) VALUES (2 , 'SAP', 'OLD','UPCOMING');
INSERT INTO STAGE_PROJECT(PROJECT_ID, DEPARTMENT, CONTRACT, SCOPE) VALUES (3 , 'DWH', 'NEW CONTRA','TARGET');
SELECT * FROM PROJECT_DATA;
SELECT * FROM STAGE_PROJECT;
This PLSQL code loop through your STAGE_PROJECT rows
If rows found in the PROJECT_DATA it will update those rows
otherwise, it will insert the row which is not found.
DECLARE
CURSOR SPCUR IS SELECT * FROM STAGE_PROJECT;
EX PLS_INTEGER;
BEGIN
FOR STAGE_PROJECT_REC IN SPCUR
LOOP
SELECT COUNT(*) INTO EX FROM PROJECT_DATA WHERE
PROJECT_ID = STAGE_PROJECT_REC.PROJECT_ID AND
DEPARTMENT = STAGE_PROJECT_REC.DEPARTMENT;
IF EX > 0 THEN
UPDATE PROJECT_DATA SET CONTRACT = STAGE_PROJECT_REC.CONTRACT,
SCOPE = STAGE_PROJECT_REC.SCOPE,
FINAL_DATE = STAGE_PROJECT_REC.FINAL_DATE
WHERE PROJECT_ID = STAGE_PROJECT_REC.PROJECT_ID AND
DEPARTMENT = STAGE_PROJECT_REC.DEPARTMENT;
ELSE
INSERT INTO PROJECT_DATA(PROJECT_ID, DEPARTMENT, CONTRACT, SCOPE, FINAL_DATE)
VALUES (STAGE_PROJECT_REC.PROJECT_ID, STAGE_PROJECT_REC.DEPARTMENT, STAGE_PROJECT_REC.CONTRACT, STAGE_PROJECT_REC.SCOPE, STAGE_PROJECT_REC.FINAL_DATE);
END IF;
END LOOP;
COMMIT;
END;
My Problem:
I have an app and users who login have a department authorization list:
DEPT1, DEPT2, DEPT3, ..., DEPT5000, DEPT5001, ...
Most users have 5,000+ departments assigned to their profile.
I am tasked with writing a data model + application code that will 'snapshot' their list of authorized departments every time a user logs in so that we may refer to what that user was authorized to do (note: the DEPT IDs are not neatly numbered like in this example).
What I've tried:
My first thought was to turn the list of departments into a long CSV string and store it as a CLOB:
CREATE TABLE UI_SECURITY_CONFIG (
SECURITY_CONFIG_ID NUMBER(19,0) NOT NULL,
DEPTSCSV CLOB NOT NULL
);
And each DEPTSCSV CLOB would be unique. If the user has the same security profile as someone else who's logged in previously, it would just select that security config. Otherwise, it would create a new row. Basically, do a select where DEPTSCSV = 'DEPT1, DEPT2, DEPT3 ...' and if it doesn't exist, insert it. But this approach failed because a huge string that big (25,000+ chars) isn't comparable:
SELECT * FROM UI_SECURITY_CONFIG WHERE DEPTSCSV = 'DEPT0001, DEPT0002, DEPT0003, ..., DEPT5001, DEPT5002'
SQL Error [1704] [42000]: ORA-01704: string literal too long
Solution attempt #2:
So then I thought about making each item in the CSV its own row in the table:
CREATE TABLE UI_SECURITY_CONFIG (
SECURITY_CONFIG_ID NUMBER(19,0) NOT NULL,
DEPTID VARCHAR2(20) NOT NULL
);
INSERT INTO UI_SECURITY_CONFIG(SECURITY_CONFIG_ID, DEPTID) VALUES(1, 'DEPT0001');
INSERT INTO UI_SECURITY_CONFIG(SECURITY_CONFIG_ID, DEPTID) VALUES(1, 'DEPT0002');
INSERT INTO UI_SECURITY_CONFIG(SECURITY_CONFIG_ID, DEPTID) VALUES(1, 'DEPT0003');
...
INSERT INTO UI_SECURITY_CONFIG(SECURITY_CONFIG_ID, DEPTID) VALUES(1, 'DEPT5001');
INSERT INTO UI_SECURITY_CONFIG(SECURITY_CONFIG_ID, DEPTID) VALUES(1, 'DEPT5002');
But I'm struggling to write the SQL select that would be an efficient matching algorithm to find if a SECURITY_CONFIG_ID exists that matches exactly the list of Departments.
I'm not even sure there is an efficient way to solve this problem.
Solution Attempt #3:
Ask Stack Overflow. What would you do?
I was able to achieve strategy #1. The Application code (Java) handled the CLOB comparison better than my SQL client (DBeaver) with PreparedStatement:
String sql = "SELECT SECURITY_CONFIG_ID FROM UI_SECURITY_CONFIG WHERE dbms_lob.compare(DEPTSCSV, ?) = 0";
String DEPTSCSV = "DEPT0001, DEPT0002, ...";
try(PreparedStatement objStmt = objConn.prepareStatement(sql)) {
Clob clob1 = objConn.createClob();
clob1.setString(1, DEPTSCSV);
objStmt.setClob(1, clob1);
ResultSet result = objStmt.executeQuery();
...
}
I got this 'Message' table.
CREATE TABLE message (
id INT PRIMARY KEY,
user_id INT NOT NULL REFERENCES users (id) ON DELETE CASCADE,
category_id INT NOT NULL REFERENCES category (id) ON DELETE CASCADE,
text VARCHAR2(4000),
media VARCHAR2(500),
creation_date DATE DEFAULT SYSDATE
);
CREATE SEQUENCE message_seq;
CREATE OR REPLACE TRIGGER message_bir
BEFORE INSERT ON message
FOR EACH ROW
BEGIN
SELECT message_seq.NEXTVAL
INTO :new.id
FROM dual;
END;
After i insert something i need the last inserted id and the date.
INSERT INTO message (user_id, category_id, media)
VALUES (1, 1, 'fdsfsd')
RETURNING id INTO :last_insert_id
The above gives me the last inserted id, but like i said i also need the creation_date. I dont want to do a select query after...
Is there a way to get 2 values back after run an insert?
You can write:
RETURNING id, creation_date INTO :last_insert_id, :last_creation_date.
See http://docs.oracle.com/cd/B28359_01/appdev.111/b28370/returninginto_clause.htm
I have table called company_emp. In that table I have 6 columns related to employees:
empid
ename
dob
doj, ...
I have another table called bday. In that I have only 2 columns; empid and dob.
I have this query:
select empid, dob
from company_emp
where dob like '01/05/2011'
It shows some list of employees.
In the same way I have queried with table bday it listed some employees.
Now I want to update the company_emp table for employees who have date '01/05/2011'.
I have tried a query like this:
update company_name a
set dob = (select dob from bday b
where b.empid=a.empid
and to_char(a.dob,'dd/mm/yyyy') = '01/05/2011'}
Then all the records in that row becoming null. How can I fix this query?
You're updating every row in the company_name/emp table.
You can fix that with a correlated subquery to make sure the row exists, or more efficiently by placing a primary or unique key on bday.empid and querying:
update (
select c.dob to_dob,
d.dob from_dob
from company_emp c join dob d on (c.empid = d.empid)
where d.dob = date '2011-05-01')
set to_dob = from_dob
Syntax not tested.
Do want to create Stored procc which updates or inserts into table based on the condition if current line does not exist in table?
This is what I have come up with so far:
PROCEDURE SP_UPDATE_EMPLOYEE
(
SSN VARCHAR2,
NAME VARCHAR2
)
AS
BEGIN
IF EXISTS(SELECT * FROM tblEMPLOYEE a where a.ssn = SSN)
--what ? just carry on to else
ELSE
INSERT INTO pb_mifid (ssn, NAME)
VALUES (SSN, NAME);
END;
Is this the way to achieve this?
This is quite a common pattern. Depending on what version of Oracle you are running, you could use the merge statement (I am not sure what version it appeared in).
create table test_merge (id integer, c2 varchar2(255));
create unique index test_merge_idx1 on test_merge(id);
merge into test_merge t
using (select 1 id, 'foobar' c2 from dual) s
on (t.id = s.id)
when matched then update set c2 = s.c2
when not matched then insert (id, c2)
values (s.id, s.c2);
Merge is intended to merge data from a source table, but you can fake it for individual rows by selecting the data from dual.
If you cannot use merge, then optimize for the most common case. Will the proc usually not find a record and need to insert it, or will it usually need to update an existing record?
If inserting will be most common, code such as the following is probably best:
begin
insert into t (columns)
values ()
exception
when dup_val_on_index then
update t set cols = values
end;
If update is the most common, then turn the procedure around:
begin
update t set cols = values;
if sql%rowcount = 0 then
-- nothing was updated, so the record doesn't exist, insert it.
insert into t (columns)
values ();
end if;
end;
You should not issue a select to check for the row and make the decision based on the result - that means you will always need to run two SQL statements, when you can get away with one most of the time (or always if you use merge). The less SQL statements you use, the better your code will perform.
BEGIN
INSERT INTO pb_mifid (ssn, NAME)
select SSN, NAME from dual
where not exists(SELECT * FROM tblEMPLOYEE a where a.ssn = SSN);
END;
UPDATE:
Attention, you should name your parameter p_ssn(distinguish to the column SSN ), and the query become:
INSERT INTO pb_mifid (ssn, NAME)
select P_SSN, NAME from dual
where not exists(SELECT * FROM tblEMPLOYEE a where a.ssn = P_SSN);
because this allways exists:
SELECT * FROM tblEMPLOYEE a where a.ssn = SSN