JarCastingPersistenceKt
Kotlin version of annotation based wrapper for SQLite and MySQL.
Note: this library uses the same packages and classes as java-persistence which makes them mutually exclusive in class path.
Releases
https://oss.sonatype.org/content/repositories/releases/org/panteleyev/persistence-kt/
API Documentation
https://petr-panteleyev.github.io/persistence-kt/persistence-kt
Implementation Details
Database
Database manipulation is beyond the scope of this API. Calling code must supply correct DataSource and ensure database does exist and proper access control is established.
Mutable Objects
Mutable object must implement mutable properties annotated as shown below:
@Table("book")
class Book (
@param:Field("id")
@get:Field(value = "id", primaryKey = true)
override var id: Integer
@param:Field("title")
@get:Field("title")
var title: String
): Record
Immutable Objects
Immutable objects are supported by annotation @RecordBuilder as shown below.
@Table("book")
class Book @RecordBuilder constructor (
@param:Field("id")
@get:Field(value = "id", primaryKey = true)
override val id: Integer
@param:Field("title")
@get:Field("title")
val title: String
): Record
Data Types
The following data types are supported:
| Java | SQLite | MySQL | Comment |
|---|---|---|---|
| int Integer |
INTEGER | INTEGER | |
| long Long |
INTEGER | BIGINT | |
| bool Boolean |
BOOLEAN | BOOLEAN | |
| String | VARCHAR (Field.length) |
VARCHAR (Field.length) |
|
| BigDecimal | VARCHAR (Field.precision + 1) |
DECIMAL (Field.precision, Field.scale) |
MySQL representation does not guarantee that retrieved value will be equal to original one by means of Object.equals(Object). Use BigDecimal.compareTo(BigDecimal) instead. |
| Date | INTEGER | BIGINT | Dates are stored as long using Date.getTime() |
Indexes and Foreign Keys
Parent Table
@Table("parent_table")
data class ParentTable : Record {
@get:Field("data")
@get:Index("data", unique = true)
var data: String?
}
This will produce the following SQL for indexed field:
CREATE UNIQUE INDEX data ON parent_table(data)
Child Table
@Table("child_table")
data class ChildTable : Record {
// ...
@get:Field("cascade_value")
@get:ForeignKey(table = ParentTable::class, field = "data",
onDelete = ReferenceOption.RESTRICT, onUpdate = ReferenceOption.CASCADE)
val cascadeValue: String?
// ...
}
This will produce the following SQL for the foreign key:
CREATE FOREIGN KEY(parent_data) REFERENCES parent_table(data) ON DELETE RESTRICT ON UPDATE CASCADE