io.ebeaninternal.dbmigration.ddlgeneration.platform.NuoDbHistoryDdl Maven / Gradle / Ivy

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composite of common runtime dependencies for all platforms

There is a newer version: 15.10.0

package io.ebeaninternal.dbmigration.ddlgeneration.platform;

import io.ebeaninternal.dbmigration.ddlgeneration.DdlBuffer;
import io.ebeaninternal.dbmigration.ddlgeneration.DdlWrite;
import io.ebeaninternal.dbmigration.model.MTable;

import java.io.IOException;

/**
 * NuoDB history support using DB triggers to maintain a history table.
 */
public class NuoDbHistoryDdl extends DbTriggerBasedHistoryDdl {

  NuoDbHistoryDdl() {
    this.now = "now()";
    this.sysPeriodEndValue = "NEW.sys_period_start";
  }

  @Override
  protected void dropTriggers(DdlBuffer buffer, String baseTable) throws IOException {

    buffer.append("drop trigger ").append(updateTriggerName(baseTable)).endOfStatement();
    buffer.append("drop trigger ").append(deleteTriggerName(baseTable)).endOfStatement();
  }

  @Override
  protected void createTriggers(DdlWrite writer, MTable table) throws IOException {

    DbTriggerUpdate update = createDbTriggerUpdate(writer, table);

    addBeforeUpdate(updateTriggerName(update.getBaseTable()), update);
    addBeforeDelete(deleteTriggerName(update.getBaseTable()), update);
  }

  @Override
  protected void updateHistoryTriggers(DbTriggerUpdate update) throws IOException {

    recreateHistoryView(update);

    DdlBuffer buffer = update.historyTriggerBuffer();
    String baseTable = update.getBaseTable();

    dropTriggers(buffer, baseTable);
    addBeforeUpdate(updateTriggerName(baseTable), update);
    addBeforeDelete(deleteTriggerName(baseTable), update);
  }

  private void addBeforeUpdate(String triggerName, DbTriggerUpdate update) throws IOException {

    DdlBuffer apply = update.historyTriggerBuffer();
    addTriggerStart(triggerName, update, apply, " before update for each row as ");
    apply.append("    NEW.sys_period_start = greatest(current_timestamp, date_add(OLD.sys_period_start, interval 1 microsecond))").endOfStatement();
    appendInsertIntoHistory(apply, update.getHistoryTable(), update.getColumns());
    addEndTrigger(apply);
  }

  private void addBeforeDelete(String triggerName, DbTriggerUpdate update) throws IOException {

    DdlBuffer apply = update.historyTriggerBuffer();
    addTriggerStart(triggerName, update, apply, " before delete for each row as");
    appendInsertIntoHistory(apply, update.getHistoryTable(), update.getColumns());
    addEndTrigger(apply);
  }

  private void addTriggerStart(String triggerName, DbTriggerUpdate update, DdlBuffer apply, String s) throws IOException {
    apply
      .append("delimiter $$").newLine()
      .append("create or replace trigger ").append(triggerName).append(" for ").append(update.getBaseTable())
      .append(s).newLine();
  }

  private void addEndTrigger(DdlBuffer apply) throws IOException {
    apply.append("end_trigger")
      .endOfStatement()
      .append("$$").newLine()
      .newLine();
  }

}