Add deferrability options to foreign constraints

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Constraints.kt

@@ -43,6 +43,28 @@ enum class ReferenceOption {
     }
 }
 
+/**
+ * Represents constraint check timing options
+ * @see <a href="https://www.postgresql.org/docs/9.5/sql-set-constraints.html">PostgreSQL Documentation</a>
+ */
+enum class DeferrabilityOption {
+    NOT_DEFERRABLE,
+    DEFERRABLE_INITIALLY_DEFERRED,
+    DEFERRABLE_INITIALLY_IMMEDIATE;
+
+    override fun toString(): String = name.replace("_", " ")
+
+    companion object {
+        /** Returns the corresponding [DeferrabilityOption] for the specified [refOption] from JDBC. */
+        fun resolveRefOptionFromJdbc(refOption: Int): DeferrabilityOption? = when (refOption) {
+            DatabaseMetaData.importedKeyNotDeferrable -> NOT_DEFERRABLE
+            DatabaseMetaData.importedKeyInitiallyDeferred -> DEFERRABLE_INITIALLY_DEFERRED
+            DatabaseMetaData.importedKeyInitiallyImmediate -> DEFERRABLE_INITIALLY_IMMEDIATE
+            else -> currentDialect.defaultDeferrabilityOption
+        }
+    }
+}
+
 /**
  * Represents a foreign key constraint.
  */
@@ -51,6 +73,7 @@ data class ForeignKeyConstraint(
         val from: Column<*>,
         private val onUpdate: ReferenceOption?,
         private val onDelete: ReferenceOption?,
+        private val deferrable: DeferrabilityOption?,
         private val name: String?
 ) : DdlAware {
     private val tx: Transaction
@@ -73,6 +96,9 @@ data class ForeignKeyConstraint(
     /** Reference option when performing delete operations. */
     val deleteRule: ReferenceOption?
         get() = onDelete ?: currentDialectIfAvailable?.defaultReferenceOption
+    /** Constraint check timing when supported. */
+    val deferrabilityRule: DeferrabilityOption?
+        get() = deferrable ?: currentDialectIfAvailable?.defaultDeferrabilityOption
     /** Name of this constraint. */
     val fkName: String
         get() = tx.db.identifierManager.cutIfNecessaryAndQuote(
@@ -93,6 +119,14 @@ data class ForeignKeyConstraint(
                 append(" ON UPDATE $updateRule")
             }
         }
+
+        deferrabilityRule?.let {
+            if (currentDialect is MysqlDialect) {
+                exposedLogger.warn("MySQL does not support deferred constraints.")
+            } else {
+                append(" $it")
+            }
+        }
     }
 
     override fun createStatement(): List<String> = listOf("ALTER TABLE $fromTable ADD $foreignKeyPart")

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/Table.kt

@@ -720,13 +720,15 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         ref: Column<T>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
     ): C = apply {
         this.foreignKey = ForeignKeyConstraint(
                 target = ref,
                 from = this,
                 onUpdate = onUpdate,
                 onDelete = onDelete,
+                deferrable = deferrable,
                 name = fkName
         )
     }
@@ -747,13 +749,15 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         ref: Column<EntityID<T>>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
     ): C = apply {
         this.foreignKey = ForeignKeyConstraint(
                 target = ref,
                 from = this,
                 onUpdate = onUpdate,
                 onDelete = onDelete,
+                deferrable = deferrable,
                 name = fkName
         )
     }
@@ -776,9 +780,10 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         refColumn: Column<T>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
     ): Column<T> {
-        val column = Column<T>(this, name, refColumn.columnType.cloneAsBaseType()).references(refColumn, onDelete, onUpdate, fkName)
+        val column = Column<T>(this, name, refColumn.columnType.cloneAsBaseType()).references(refColumn, onDelete, onUpdate, deferrable, fkName)
         _columns.addColumn(column)
         return column
     }
@@ -803,10 +808,11 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         refColumn: Column<E>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
     ): Column<E> {
         val entityIDColumn = entityId(name, (refColumn.columnType as EntityIDColumnType<T>).idColumn) as Column<E>
-        return entityIDColumn.references(refColumn, onDelete, onUpdate, fkName)
+        return entityIDColumn.references(refColumn, onDelete, onUpdate, deferrable, fkName)
     }
 
     /**
@@ -827,8 +833,9 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         foreign: IdTable<T>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
-    ): Column<EntityID<T>> = entityId(name, foreign).references(foreign.id, onDelete, onUpdate, fkName)
+    ): Column<EntityID<T>> = entityId(name, foreign).references(foreign.id, onDelete, onUpdate, deferrable, fkName)
 
     /**
      * Creates a column with the specified [name] with an optional reference to the [refColumn] column with [onDelete], [onUpdate], and [fkName] options.
@@ -848,8 +855,9 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         refColumn: Column<T>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
-    ): Column<T?> = Column<T>(this, name, refColumn.columnType.cloneAsBaseType()).references(refColumn, onDelete, onUpdate, fkName).nullable()
+    ): Column<T?> = Column<T>(this, name, refColumn.columnType.cloneAsBaseType()).references(refColumn, onDelete, onUpdate, deferrable, fkName).nullable()
 
     /**
      * Creates a column with the specified [name] with an optional reference to the [refColumn] column with [onDelete], [onUpdate], and [fkName] options.
@@ -871,10 +879,11 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         refColumn: Column<E>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
     ): Column<E?> {
         val entityIdColumn = entityId(name, (refColumn.columnType as EntityIDColumnType<T>).idColumn) as Column<E>
-        return entityIdColumn.references(refColumn, onDelete, onUpdate, fkName).nullable()
+        return entityIdColumn.references(refColumn, onDelete, onUpdate, deferrable, fkName).nullable()
     }
 
     /**
@@ -895,8 +904,9 @@ open class Table(name: String = "") : ColumnSet(), DdlAware {
         foreign: IdTable<T>,
         onDelete: ReferenceOption? = null,
         onUpdate: ReferenceOption? = null,
+        deferrable: DeferrabilityOption? = null,
         fkName: String? = null
-    ): Column<EntityID<T>?> = entityId(name, foreign).references(foreign.id, onDelete, onUpdate, fkName).nullable()
+    ): Column<EntityID<T>?> = entityId(name, foreign).references(foreign.id, onDelete, onUpdate, deferrable, fkName).nullable()
 
     // Miscellaneous
 

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Default.kt

@@ -512,6 +512,8 @@ interface DatabaseDialect {
     val needsSequenceToAutoInc: Boolean get() = false
     /** Returns the default reference option for the dialect. */
     val defaultReferenceOption: ReferenceOption get() = ReferenceOption.RESTRICT
+    /** Returns the default constraint timing for the dialect. */
+    val defaultDeferrabilityOption: DeferrabilityOption? get() = null
     /** Returns `true` if the dialect requires the use of quotes when using symbols in object names, `false` otherwise. */
     val needsQuotesWhenSymbolsInNames: Boolean get() = true
     /** Returns `true` if the dialect supports returning multiple generated keys as a result of an insert operation, `false` otherwise. */

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/vendors/Mysql.kt

@@ -172,6 +172,7 @@ open class MysqlDialect : VendorDialect(dialectName, MysqlDataTypeProvider, Mysq
                             from = fromColumn,
                             onUpdate = constraintUpdateRule,
                             onDelete = constraintDeleteRule,
+                            deferrable = null,
                             name = constraintName
                         )
                     )

exposed-jdbc/src/main/kotlin/org/jetbrains/exposed/sql/statements/jdbc/JdbcDatabaseMetadataImpl.kt

@@ -191,11 +191,14 @@ class JdbcDatabaseMetadataImpl(database: String, val metadata: DatabaseMetaData)
                 }
                 val constraintUpdateRule = ReferenceOption.resolveRefOptionFromJdbc(getInt("UPDATE_RULE"))
                 val constraintDeleteRule = ReferenceOption.resolveRefOptionFromJdbc(getInt("DELETE_RULE"))
+                val constraintDeferrable = DeferrabilityOption.resolveRefOptionFromJdbc(getInt("DEFERRABILITY"))
+
                 ForeignKeyConstraint(
                         target = targetColumn,
                         from = fromColumn,
                         onUpdate = constraintUpdateRule,
                         onDelete = constraintDeleteRule,
+                        deferrable = constraintDeferrable,
                         name = constraintName
                 )
             }.filterNotNull()