Now, let us map the Id column of our entity: = "id", nullable = false)ĭo we need to set the column “unique” property to “true” when using the annotation? For simplicity reasons, we will leave the default value in our example. If left empty, the default value is “AUTO”, which means that the JPA provider will use the strategy that the persistence provider (for example, our Postgres DBMS) offers. The generation strategy can be set in the GeneratedValue annotation. annotation indicates that the column value is not manually set, but is generated via a specific strategy, such as a SequenceGenerator, a TableGenerator, etc. If the annotation is missing, then the column name is assumed to be the same as the name of the field/parameter in the Java class. The annotation is usually combined with the annotation in order to indicate the column name on the database side, nullability, length, etc. The ID field can be any Java primitive data type, String,, , BigDecimal or a BigInteger. Public void setBranchCode(String branchCode) annotation indicates that the given column holds the primary key value of the entity. = "branch_code", unique = true, nullable = false) Therefore we need to set the “unique” column property to “true”. Notice that we added a unique constraint in the table creation script. The next step is to map the “branch_code” column. This.name = "zip_code", nullable = false, length = 50) So, let us now map the “zip_code” and the “name” columns. If the default value is different than that on the database side, then the length parameter should be set. length (int): If the column represents a String/Variable character, then the length represents the maximum length of that string.Usually we would set this to false if we do not want a column to be modified after initial insertion. If set to false, then update statements will not include the column. updateable (boolean): Indicates if the column should be included in SQL update statements issued by the JPA implementation provide. ![]() ![]() If set to false, then insert statements will not include the column.
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