Aug 23, 2013 Oracle Java JDBC: Get Primary Key of Inserted record by Viral Patel August 23, 2013 Here is a small write-up which should help those who still write plain Java JDBC code. Primary Key Generation Using Oracle's Sequence. Oracle provides the sequence utility to automatically generate unique primary keys. To use this utility to auto-generate primary keys for a CMP entity bean, you must create a sequence table and use the @AutomaticKeyGeneration annotation to point to this table.
The
AUTO_INCREMENT attribute can be used to generate a unique identity for new rows:
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Which returns:
No value was specified for the
AUTO_INCREMENT column, so MySQL assigned sequence numbers automatically. You can also explicitly assign 0 to the column to generate sequence numbers, unless the NO_AUTO_VALUE_ON_ZERO SQL mode is enabled. For example:
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If the column is declared
NOT NULL , it is also possible to assign NULL to the column to generate sequence numbers. For example:
When you insert any other value into an
AUTO_INCREMENT column, the column is set to that value and the sequence is reset so that the next automatically generated value follows sequentially from the largest column value. For example:
Updating an existing
AUTO_INCREMENT column value in an InnoDB table does not reset the AUTO_INCREMENT sequence as it does for MyISAM and NDB tables.
You can retrieve the most recent automatically generated
AUTO_INCREMENT value with the LAST_INSERT_ID() SQL function or the mysql_insert_id() C API function. These functions are connection-specific, so their return values are not affected by another connection which is also performing inserts.
Use the smallest integer data type for the
AUTO_INCREMENT column that is large enough to hold the maximum sequence value you will need. When the column reaches the upper limit of the data type, the next attempt to generate a sequence number fails. Use the UNSIGNED attribute if possible to allow a greater range. For example, if you use TINYINT , the maximum permissible sequence number is 127. For TINYINT UNSIGNED , the maximum is 255. See Section 11.1.2, “Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT” for the ranges of all the integer types.
For a multiple-row insert,
LAST_INSERT_ID() and mysql_insert_id() actually return the AUTO_INCREMENT key from the first of the inserted rows. This enables multiple-row inserts to be reproduced correctly on other servers in a replication setup.
To start with an
AUTO_INCREMENT value other than 1, set that value with CREATE TABLE or ALTER TABLE , like this:
Auto Generated Primary Key Oracle Sql
For information about
AUTO_INCREMENT usage specific to InnoDB , see Section 14.9.1.4, “AUTO_INCREMENT Handling in InnoDB”.
More information about
AUTO_INCREMENT is available here:
AUTO INCREMENT Field
Auto-increment allows a unique number to be generated automatically when a new record is inserted into a table.
Often this is the primary key field that we would like to be created automatically every time a new record is inserted.
Syntax for MySQL
The following SQL statement defines the 'Personid' column to be an auto-increment primary key field in the 'Persons' table:
CREATE TABLE Persons (
Personid int NOT NULL AUTO_INCREMENT, LastName varchar(255) NOT NULL, FirstName varchar(255), Age int, PRIMARY KEY (Personid) );
MySQL uses the AUTO_INCREMENT keyword to perform an auto-increment feature.
By default, the starting value for AUTO_INCREMENT is 1, and it will increment by 1 for each new record.
To let the AUTO_INCREMENT sequence start with another value, use the following SQL statement:
To insert a new record into the 'Persons' table, we will NOT have to specify a value for the 'Personid' column (a unique value will be added automatically):
INSERT INTO Persons (FirstName,LastName)
VALUES ('Lars','Monsen'); Jpa Auto Increment Primary Key Oracle
The SQL statement above would insert a new record into the 'Persons' table. The 'Personid' column would be assigned a unique value. The 'FirstName' column would be set to 'Lars' and the 'LastName' column would be set to 'Monsen'.
Syntax for SQL Server
The following SQL statement defines the 'Personid' column to be an auto-increment primary key field in the 'Persons' table:
CREATE TABLE Persons (
Personid int IDENTITY(1,1) PRIMARY KEY, LastName varchar(255) NOT NULL, FirstName varchar(255), Age int );
The MS SQL Server uses the IDENTITY keyword to perform an auto-increment feature.
In the example above, the starting value for IDENTITY is 1, and it will increment by 1 for each new record.
Tip: To specify that the 'Personid' column should start at value 10 and increment by 5, change it to IDENTITY(10,5).
To insert a new record into the 'Persons' table, we will NOT have to specify a value for the 'Personid' column (a unique value will be added automatically):
INSERT INTO Persons (FirstName,LastName)
VALUES ('Lars','Monsen');
The SQL statement above would insert a new record into the 'Persons' table. The 'Personid' column would be assigned a unique value. The 'FirstName' column would be set to 'Lars' and the 'LastName' column would be set to 'Monsen'.
Syntax for Access
The following SQL statement defines the 'Personid' column to be an auto-increment primary key field in the 'Persons' table:
CREATE TABLE Persons (
Personid AUTOINCREMENT PRIMARY KEY, LastName varchar(255) NOT NULL, FirstName varchar(255), Age int );
The MS Access uses the AUTOINCREMENT keyword to perform an auto-increment feature.
By default, the starting value for AUTOINCREMENT is 1, and it will increment by 1 for each new record.
Tip: To specify that the 'Personid' column should start at value 10 and increment by 5, change the autoincrement to AUTOINCREMENT(10,5).
To insert a new record into the 'Persons' table, we will NOT have to specify a value for the 'Personid' column (a unique value will be added automatically):
INSERT INTO Persons (FirstName,LastName)
VALUES ('Lars','Monsen');
The SQL statement above would insert a new record into the 'Persons' table. The 'Personid' column would be assigned a unique value. The 'FirstName' column would be set to 'Lars' and the 'LastName' column would be set to 'Monsen'.
Syntax for Oracle
In Oracle the code is a little bit more tricky.
You will have to create an auto-increment field with the sequence object (this object generates a number sequence).
Use the following CREATE SEQUENCE syntax:
CREATE SEQUENCE seq_person
MINVALUE 1 START WITH 1 INCREMENT BY 1 CACHE 10;
The code above creates a sequence object called seq_person, that starts with 1 and will increment by 1. It will also cache up to 10 values for performance. The cache option specifies how many sequence values will be stored in memory for faster access.
To insert a new record into the 'Persons' table, we will have to use the nextval function (this function retrieves the next value from seq_person sequence):
INSERT INTO Persons (Personid,FirstName,LastName)
VALUES (seq_person.nextval,'Lars','Monsen');
The SQL statement above would insert a new record into the 'Persons' table. The 'Personid' column would be assigned the next number from the seq_person sequence. The 'FirstName' column would be set to 'Lars' and the 'LastName' column would be set to 'Monsen'.
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