Identity column in java db - java

Is there a way to add an identity column into java DB using netbeans.
the table is PAYMENTS
column name is ID

First hit on google for 'java db identity':
http://www.herongyang.com/JDBC/Derby-DML-Primary-Key-IDENTITY-Column.html
In other words use:
GENERATED ALWAYS AS IDENTITY
or
GENERATED BY DEFAULT AS IDENTITY
As part of your primary key declaration.

Related

I need to update the id along with the name and desc - SQL

I am selecting the id using
SELECT SCRTY_RISK_AREA_UI_AREA_ID_SQ.nextval as\"riskAreaNo\" FROM DUAL
This sql query from the database.
Now I need to update the name and description of the already existing data along with the id
UPDATE SCRTY_RISK_AREA
SET AREA_NAME= :areaName, AREA_DESC= :areaDesc,IS_ACTIVE='N'
WHERE UI_AREA_ID = :uiareaId");
Am updating using the above query.
Can anybody help me how to insert or generate the new id. am new to sql not sure how to generate new id
I am not sure how to update along with the id since i generate the id using sequence
If you're inserting a new row, then
insert into scrty_risk_area (id, area_name) values
(scrty_risk_area_ui_area_id_sq.nextval, :areaName);
If you're updating existing ID values (probably not a good idea, especially if it is a primary key, not to mention if it is referenced by some foreign keys):
update scrty_risk_area set
id = scrty_risk_area_ui_area_id_sq.nextval;

Query for the allowed values in a constraint

I want to extract values from a CHECK constraint on a database table. The code is:
CONSTRAINT Shop_check_serviceType CHECK (service_type IN ('food or drink', 'entertainment', 'retail'))
In Postgres 12 there is a column named consrc in pg_catalog.pg_constraint. But I use Postgres 14 and I don't know how to extract the values there. I have tried to search the manual without success.
Use the dedicated function pg_get_constraintdef() to reverse-engineer the SQL-DDL code of constraint definition.
SELECT pg_get_constraintdef(oid)
FROM pg_catalog.pg_constraint
WHERE contype = 'c' -- CHECK constraint
AND conrelid = 'public.my_table'::regclass -- your table name here
AND connname = 'shop_check_servicetype'; -- lower-cased?
If you did not double-quote the constraint name "Shop_check_serviceType" it has been converted to lower-case.
Related:
Delete rows with foreign key in PostgreSQL
BTW, the (redundant) column consrc existed up to Postgres 11 and had already been dropped from pg_catalog.pg_constraint in Postgres 12. pg_get_constraintdef() reproduces what used to be in that column.
Quoting the release notes of Postgres 12:
Remove obsolete pg_constraint.consrc column (Peter Eisentraut)
This column has been deprecated for a long time, because it did not
update in response to other catalog changes (such as column
renamings). The recommended way to get a text version of a check
constraint's expression from pg_constraint is pg_get_expr(conbin, conrelid). pg_get_constraintdef() is also a useful alternative.

create table with foreign key column, AutoNumber primary key column, and default values for dates

I need to create a table using Jackcess library which consists of foreign key reference column and primary key column with auto increment. Also, how can I specify default values for all the columns like Date/Timestamps?
In the Jackcess cookbook,
I found one example to create table but it is not covering the above cases.
How can I implement the above?
Creating Relationships
Jackcess 2.1.5 added the ability to create Relationships (and hence Foreign Key Constraints) using RelationshipBuilder, e.g.
// example in the JavaDoc for RelationshipBuilder:
//
Relationship rel = new RelationshipBuilder("FromTable", "ToTable")
.addColumns("ID", "FK_ID")
.setReferentialIntegrity()
.setCascadeDeletes()
.toRelationship(db);
Other Items
Creating a table with an AutoNumber field:
As shown in the cookbook, that is done using ColumnBuilder#setAutonumber(true).
Setting a default value for a field:
That can be done by creating a new Property named "DefaultValue" for the column:
Table tbl = db.getTable("Donations");
Column col = tbl.getColumn("DonationDate");
PropertyMap pm = col.getProperties();
pm.put("DefaultValue", "Date()");
pm.save();
Note, however, that while this default value will be used by ACE/Jet and UCanAccess, Jackcess itself does not currently respect the "DefaultValue" property when it adds new rows to a table.

Hibernate not creating foreign key constraint on MySQL

I am using Hibernate and MySQL when my mapping for table is done and when I look at my DB table its created successfully but their is no foreign key constraint but column is created.
When I try to insert record in child table and when I put id which not exist in parent table in foreign key column then also that row get inserted.
My table engine is innoDB.
If I change dialect to MS-SQL then table get created with foreign key constraint.
Sorry users,
I got issue with this actually my DBA not given permission for ALTER command.
so thats why, when an table with foreign Key is going to create first CREATE command is executed and then ALTER command is executed.
In my case CREATE command is executed successfully but ALTER command does not coz its dnt have permission.

incrementing the primary key by default,as the records are entered in the databases

i was doing a java program,as i was creating my second or third simple program of jdbc,i was entering the information about students in a table,in which there were four fields, the name,city & the roll no of the student which were added manually by the user through the java program(code),but i want that the fourth field id,(which is primary key,hence must be unique)must be generated automatically during the addition of the complete record,& it must be the value one more then the previous id's value present in the table......How could i do this??
i am not too good at sql queries..:)
which IDE are you using????
CREATE TABLE "student"
(
"stud_id" INT not null primary key
GENERATED ALWAYS AS IDENTITY
(START WITH 1, INCREMENT BY 1),
"NAME" VARCHAR(50),
"CITY" VARCHAR(50),
"ROLL NO." INTEGER
);
It should be done via server (sql) side, try to read about auto increment for instance MySQL auto increment
And Yes, you have not set up auto increment from Java Side, for example if you have student table with some fields like id (auto_increment), name and age you should set just name and age from java side, id will be added from SQL side.

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