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Background: I am building a Springboot+mySQL app that uses Spring Data JPA native queries (i.e. #Query(value = "...", nativeQuery = true) to retrieve database data.
We have to use the same SQL in every query we write to enable certain functionality (this can be seen in the example below). And wanted a way to remove this duplicate SQL and instead only declare it once. An option presented was to pass a dynamic SQL string into a stored procedure and then build a prepared statement by concatenating this dynamic SQL string with our static shared SQL string (show in example below).
Question:
This doesn't seem like a good idea to me, but I am not knowledgeable enough about databases to given the exact technical reasons. Is the below example safe, reasonable, and best-practice? Are there ways to mitigate issues with this approach, or are there other approaches to use instead?
Basic setup code:
-- create tables
CREATE TABLE docs (
id INTEGER PRIMARY KEY,
rev INTEGER NOT NULL,
content VARCHAR(30) NOT NULL
);
CREATE TABLE more_docs (
id INTEGER PRIMARY KEY,
more_content VARCHAR(30) NOT NULL
);
CREATE TABLE docs_metadata (
id INTEGER PRIMARY KEY,
letter VARCHAR(30) NOT NULL
);
CREATE TABLE metadata_nums (
id INTEGER PRIMARY KEY,
metadata_id INTEGER,
num INTEGER NOT NULL
);
-- insert some values
INSERT INTO docs VALUES (1, 1, 'abc');
INSERT INTO docs VALUES (2, 1, 'def');
INSERT INTO docs VALUES (3, 2, 'ghi');
INSERT INTO docs VALUES (4, 1, 'jkl');
INSERT INTO more_docs VALUES (1, 'aaa');
INSERT INTO more_docs VALUES (2, 'bbb');
INSERT INTO more_docs VALUES (3, 'ccc');
INSERT INTO more_docs VALUES (4, 'ddd');
INSERT INTO docs_metadata VALUES (1, 'a');
INSERT INTO docs_metadata VALUES (2, 'b');
INSERT INTO docs_metadata VALUES (3, 'c');
INSERT INTO docs_metadata VALUES (4, 'd');
INSERT INTO metadata_nums VALUES (1, 1, 5);
INSERT INTO metadata_nums VALUES (2, 1, 6);
INSERT INTO metadata_nums VALUES (3, 2, 5);
INSERT INTO metadata_nums VALUES (4, 2, 6);
INSERT INTO metadata_nums VALUES (5, 3, 5);
INSERT INTO metadata_nums VALUES (6, 3, 6);
INSERT INTO metadata_nums VALUES (7, 4, 5);
INSERT INTO metadata_nums VALUES (8, 4, 6);
Approach in question:
-- create stored procedure
DELIMITER //
CREATE PROCEDURE FILTER_EVAL (IN dynamic_statement TEXT, IN num INT, IN letter VARCHAR(1))
BEGIN
SET #dynamic_statement := CONCAT("SELECT X.* FROM (", dynamic_statement, ") X INNER JOIN (SELECT DM.*, MN.num FROM docs_metadata DM INNER JOIN metadata_nums MN ON DM.id = MN.metadata_id) M ON X.id = M.id WHERE M.num = ", num, " AND M.letter = '", letter, "'");
PREPARE prepared_statement FROM #dynamic_statement;
EXECUTE prepared_statement;
DEALLOCATE PREPARE prepared_statement;
END//
DELIMITER ;
-- fetch some values
CALL FILTER_EVAL("SELECT * FROM docs WHERE rev = 1", 5, 'b')
I am attempting to use a trigger to prevent an insert when the table reaches a certain number of values
my trigger is the following
DELIMITER //
CREATE TRIGGER validate_insert /*create trigger to validate updates */
BEFORE INSERT ON trainer_party_members
FOR EACH ROW
SET #trainernumber=NULL;
SELECT COUNT(trainer_party_members.trainer_id) INTO #trainernumber FROM trainer_party_members WHERE trainer_party_members.trainer_id=trainer_id;
IF (#trainernumber=6) THEN
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = "maximum amount of trainers";
END IF;
//
DELIMITER ;
it is supposed to stop inserts when reaches 6. i am not sure why it is not working
thought it may be a problem with my select statement
inserting into the trainer_party_memebers table looks like the following
INSERT INTO trainer_party_members (pokemon_id, trainer_id)
VALUES (1, 1), -- Trade this one (Will's Pikachu)
(2, 1),
(3, 1),
(4, 1),
(5, 1),
(6, 1),
(7, 1),
(11, 2); -- for this one. (Koga's Squirtle)
theoretically it should prevent the (7,1) value from entering
INSERT INTO Employees (empId,name,salary,Email_id,DOB)
VALUES
('1','stephen','30000','stephen#gmail.com','1999-02-16'),
('2','andew','40000','andew#gmail.com','1995-12-09'),
('3','dev','16000','dev#gmail.com','1992-08-16'),
('4','jackson','25000','jack#gmail.com','1992-08-16'),
('5','shayam','33000','shaym#gmail.com','1992-08-16'),
('6','abc','31000','abc#gmail.com','1992-08-16'),
('7','xyz','32500','xyz#gmail.com','1992-08-16'),
('8','San','22000','san123#gmail.com','1992-08-16'),
('9','Sonu','29000','hkyadav#gmail.com','1992-08-16');
NOW i added one more column to this existing table.
ALTER TABLE EMPLOYEES
ADD age varchar(10);
INSERT INTO EMPLOYEES (age)
VALUES
(
('21'),
('22'),
('32'),
('35'),
('45'),
('39'),
('28'),
('26'),
('36')
);
I'm getting Error Code: 1136. Column count doesn't match value count at row 1
The above exception is thrown when the number of columns in the insert statement is lesser than the number of values in the query. Please check the column and try to insert the value manually for the first time then run the insert script.
Correct syntax is
INSERT INTO EMPLOYEES (age)
VALUES
(21),
(22),
(32),
(35),
(45),
(39),
(28),
(26),
(36)
;
This either will add new rows with all but age column NULL or will fail if some column is declared NOT NULL and has no DEFAULT value.
Provided the goal is not to add new rows but to update existing ones you need an UPDATE statement, kind of
update EMPLOYEES e,
(values
row (1, 21),
row (2, 22),
row (3, 32),
row (4, 35),
row (5, 45),
row (6, 39),
row (7, 28),
row (8, 26),
row (9, 36)
) t(empId, age)
set e.age = t.age
where e.empId = t.empId;
update EMPLOYEES e,
(values
row (1, 21),
row (2, 22),
row (3, 32),
row (4, 35),
row (5, 45),
row (6, 39),
row (7, 28),
row (8, 26),
row (9, 36)
) t(empId, age)
set e.age = t.age
where e.empId = t.empId;
I am trying to make a stored procedure that takes a name/or number and returns a specific value for that name/number
So in this code, I am trying to write a stored procedure taht takes a company name or the cvr number and return the degree of compliance for that company
DROP DATABASE IF EXISTS DRCS;
CREATE DATABASE DRCS;
USE DRCS;
CREATE TABLE Companies (
ID INT not null,
Name varchar(255),
primary key (ID)
);
CREATE TABLE CVR (
ID INT not null,
CVR_Number INT
);
CREATE TABLE Compliance (
ID INT not null,
Complaince_level varchar(255)
);
CREATE TABLE GDPR (
ID INT not null,
GDPR_steps varchar(255)
);
INSERT INTO Companies VALUES
(1, 'TDC'),
(2, 'MAERSK'),
(3, 'LEGO'),
(4, 'SAS'),
(5, 'Carlsberg');
INSERT INTO CVR VALUES
(11, '14773908'),
(12, '32345794'),
(13, '47458714'),
(14, '56994912'),
(15, '61056416');
INSERT INTO Compliance VALUES
(21, '10%'),
(22, '20%'),
(23, '40%'),
(24, '60%'),
(25, '80%');
INSERT INTO GDPR VALUES
(31, '1. Awareness'),
(32, '2. Information you hold'),
(33, '3. Communication privacy information'),
(34, '4. Individuals rights'),
(35, '5. Subject access requests');
#HERE MY PROBLEM STARTS
DELIMITER $$
CREATE PROCEDURE DoC()
BEGIN
SELECT * FROM Companies , CVR, Compliance, GDPR;
END $$
DELIMITER ;
CALL DoC;
There is no relationship between the four tables!
Create rows with common id like id = 1,2,3,4 for all tables and then do a join and then try to list the fields you want to view.
INSERT INTO Companies VALUES
(1, 'TDC'),
(2, 'MAERSK'),
(3, 'LEGO'),
(4, 'SAS'),
(5, 'Carlsberg');
INSERT INTO CVR VALUES
(1, '14773908'),
(2, '32345794'),
(3, '47458714'),
(4, '56994912'),
(5, '61056416');
INSERT INTO Compliance VALUES
(1, '10%'),
(2, '20%'),
(3, '40%'),
(4, '60%'),
(5, '80%');
INSERT INTO GDPR VALUES
(1, '1. Awareness'),
(2, '2. Information you hold'),
(3, '3. Communication privacy information'),
(4, '4. Individuals rights'),
(5, '5. Subject access requests');
select c.id,v.cvr_Number from Companies c, cvr v where c.id = v.id
Similarly add more tables by joining with id. You don't need a procedure to this and a procedure is not designed for this.
You can make with union query for all table. But all select query of clomum count should be same.
DELIMITER $$
CREATE PROCEDURE DoC()
SELECT A.id,A.name FROM
( SELECT id as id , name as name FROM Companies
UNION ALL
SELECT id as id , name as name FROM CVR
UNION ALL
SELECT id as id , name as name FROM Compliance
UNION ALL
SELECT id as id , name as name FROM GDPR) as A
END $$
DELIMITER ;
Following the posting,
TSQL Variable With List of Values for IN Clause
I formed a table variable of varchar, e.g.
Declare #myList_1(Id varchar(2))
Insert into #myList_1
Select id from (VALUES ('x1')) AS tbl(id)
Insert into #myList_1
Select id from (VALUES ('x2')) AS tbl(id)
Insert into #myList_1
Select id from (VALUES ('x3')) AS tbl(id)
However, I need to extend this concept so that I can do something such as a "like comparison"
e.g.:
myTable.myCol like ('%' + #myList_1 + '%')
above: SSMS 2008 r2 gives error: 'Must declare the scalar variable #myList_1'
If possible, I'd like to do this without an iterator or looping construct ...
Let's assume following testing data and tables structure.
-- Create test table
CREATE TABLE [dbo].[myTable](
[Id] [int] NOT NULL PRIMARY KEY,
[myCol] [varchar](100) NULL)
GO
-- Insert test data
INSERT INTO myTable(Id, myCol)
VALUES (1, 'Bladder cancer'),
(2, 'Lung cancer'),
(3, 'Brain cancer'),
(4, 'Melanoma'),
(5, 'Breast cancer'),
(6, 'Non-Hodgkin lymphoma'),
(7, 'Cervical cancer'),
(8, 'Ovarian cancer'),
(9, 'Cardiovascular disease'),
(10, 'Nerve damage'),
(11, 'Kidney damage'),
(12, 'Eye damage'),
(13, 'Foot damage'),
(14, 'Skin conditions'),
(15, 'Alzheimer''s disease'),
(16, 'Hearing impairment')
GO
Now the actual SQL would be based on joining the table where you want to do search with table variable #myList_1
-- Create list of items to look for
Declare #myList_1 table(Id varchar(20))
Insert into #myList_1
Select id from (VALUES ('cancer')) AS tbl(id)
Insert into #myList_1
Select id from (VALUES ('Melanoma')) AS tbl(id)
Insert into #myList_1
Select id from (VALUES ('lymphoma')) AS tbl(id)
-- Do query
SELECT myTable.Id, myTable.myCol
FROM myTable
JOIN #myList_1 as ItemsList
ON myTable.myCol like '%' + ItemsList.Id + '%'
In this simple case where myCol could match just single value in the #myList_1 this should be enough, but for cases where possible that myCol could match multiple values in the #myList_1 you should add DISTINCT to the query
-- Do query
SELECT DISTINCT myTable.Id, myTable.myCol
FROM myTable
JOIN #myList_1 as ItemsList
ON myTable.myCol like '%' + ItemsList.Id + '%'