package liquibase.change.core;
   
   import liquibase.change.AbstractChange;
   import liquibase.change.ChangeMetaData;
   import liquibase.database.Database;
   import liquibase.database.core.SQLiteDatabase;
   import liquibase.statement.SqlStatement;
   import liquibase.statement.core.DropForeignKeyConstraintStatement;
   
  /**
   * Drops an existing foreign key constraint.
   */
  public class DropForeignKeyConstraintChange extends AbstractChange {
      private String baseTableSchemaName;
      private String baseTableName;
      private String constraintName;
  
      public DropForeignKeyConstraintChange() {
          super("dropForeignKeyConstraint", "Drop Foreign Key Constraint", ChangeMetaData.PRIORITY_DEFAULT);
      }
  
      public String getBaseTableSchemaName() {
          return baseTableSchemaName;
      }
  
      public void setBaseTableSchemaName(String baseTableSchemaName) {
          this.baseTableSchemaName = baseTableSchemaName;
      }
  
      public String getBaseTableName() {
          return baseTableName;
      }
  
      public void setBaseTableName(String baseTableName) {
          this.baseTableName = baseTableName;
      }
  
      public String getConstraintName() {
          return constraintName;
      }
  
      public void setConstraintName(String constraintName) {
          this.constraintName = constraintName;
      }
  
      public SqlStatement[] generateStatements(Database database) {
  
          if (database instanceof SQLiteDatabase) {
              // return special statements for SQLite databases
              return generateStatementsForSQLiteDatabase(database);
          }
  
          return new SqlStatement[] { new DropForeignKeyConstraintStatement(
                  getBaseTableSchemaName() == null ? database.getDefaultSchemaName() : getBaseTableSchemaName(),
                  getBaseTableName(), getConstraintName()), };
      }
  
      private SqlStatement[] generateStatementsForSQLiteDatabase(Database database) {
          // SQLite does not support foreign keys until now.
          // See for more information: http://www.sqlite.org/omitted.html
          // Therefore this is an empty operation...
          return new SqlStatement[] {};
      }
  
      public String getConfirmationMessage() {
          return "Foreign key " + getConstraintName() + " dropped";
      }
  }