#1782 - ENH: Add truncate(Class<?>... types) and truncate(String... tables)

src/main/java/io/ebean/DB.java

@@ -1237,4 +1237,18 @@ public class DB {
     return getDefault().json();
   }
 
+  /**
+   * Truncate the base tables for the given bean types.
+   */
+  public static void truncate(Class<?>... types) {
+    getDefault().truncate(types);
+  }
+
+  /**
+   * Truncate the given tables.
+   */
+  public static void truncate(String... tables) {
+    getDefault().truncate(tables);
+  }
+
 }

src/main/java/io/ebean/Database.java

@@ -1580,4 +1580,15 @@ public interface Database {
    * </p>
    */
   <T> Set<String> validateQuery(Query<T> query);
+
+  /**
+   * Truncate all the given tables.
+   */
+  void truncate(String... tables);
+
+  /**
+   * Truncate the base tables for the given bean types.
+   */
+  void truncate(Class<?>... tables);
+
 }

src/main/java/io/ebean/config/dbplatform/DatabasePlatform.java

@@ -139,6 +139,10 @@ public class DatabasePlatform {
    */
   protected Platform platform = Platform.GENERIC;
 
+  protected String truncateTable = "truncate table %s";
+  protected String truncateTableBefore;
+  protected String truncateTableAfter;
+
   protected String columnAliasPrefix = "c";
 
   protected String tableAliasPlaceHolder = "${ta}";
@@ -708,6 +712,27 @@ public class DatabasePlatform {
     return persistBatchOnCascade;
   }
 
+  /**
+   * Return a statement to truncate a table.
+   */
+  public String truncateStatement(String table) {
+    return String.format(truncateTable, table);
+  }
+
+  /**
+   * Return a statement to execute prior to truncate (like disable foreign keys for mysql).
+   */
+  public String truncateStatementBefore() {
+    return truncateTableBefore;
+  }
+
+  /**
+   * Return a statement to execute after truncate (like enable foreign keys for mysql).
+   */
+  public String truncateStatementAfter() {
+    return truncateTableAfter;
+  }
+
   /**
    * Create the DB schema if it does not exist.
    */

src/main/java/io/ebean/config/dbplatform/db2/DB2Platform.java

@@ -22,6 +22,7 @@ public class DB2Platform extends DatabasePlatform {
     this.platform = Platform.DB2;
     this.maxTableNameLength = 18;
     this.maxConstraintNameLength = 18;
+    this.truncateTable = "truncate table %s reuse storage ignore delete triggers immediate";
     this.sqlLimiter = new Db2SqlLimiter();
 
     this.dbIdentity.setSupportsGetGeneratedKeys(true);

src/main/java/io/ebean/config/dbplatform/h2/H2Platform.java

@@ -26,7 +26,8 @@ public class H2Platform extends DatabasePlatform {
     this.supportsDeleteTableAlias = true;
     this.dbDefaultValue.setNow("now()");
     this.columnAliasPrefix = null;
-
+    //this.truncateTableBefore = "set referential_integrity false";
+    //this.truncateTableAfter = "set referential_integrity true";
     this.exceptionTranslator =
       new SqlErrorCodes()
         .addAcquireLock("50200","HYT00")

src/main/java/io/ebean/config/dbplatform/hana/HanaPlatform.java

@@ -18,7 +18,6 @@ public class HanaPlatform extends DatabasePlatform {
     this.persistBatchOnCascade = PersistBatch.NONE;
     this.supportsResultSetConcurrencyModeUpdatable = false;
     this.columnAliasPrefix = null;
-
     this.historySupport = new HanaHistorySupport();
     this.basicSqlLimiter = new HanaBasicSqlLimiter();
 

src/main/java/io/ebean/config/dbplatform/hsqldb/HsqldbPlatform.java

@@ -21,7 +21,7 @@ public class HsqldbPlatform extends DatabasePlatform {
     super();
     this.platform = Platform.HSQLDB;
     this.dbEncrypt = new H2DbEncrypt();
-
+    this.truncateTable = "delete from %s";
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
     this.dbIdentity.setSupportsSequence(true);

src/main/java/io/ebean/config/dbplatform/mysql/MySqlPlatform.java

@@ -31,7 +31,8 @@ public class MySqlPlatform extends DatabasePlatform {
     this.dbEncrypt = new MySqlDbEncrypt();
     this.historySupport = new MySqlHistorySupport();
     this.columnAliasPrefix = null;
-
+    //this.truncateTableBefore = "set foreign_key_checks = 0";
+    //this.truncateTableAfter = "set foreign_key_checks = 1";
     this.dbIdentity.setIdType(IdType.IDENTITY);
     this.dbIdentity.setSupportsGetGeneratedKeys(true);
     this.dbIdentity.setSupportsIdentity(true);

src/main/java/io/ebean/config/dbplatform/oracle/OraclePlatform.java

@@ -30,7 +30,7 @@ public class OraclePlatform extends DatabasePlatform {
     this.sqlLimiter = new RownumSqlLimiter();
     this.basicSqlLimiter = new BasicSqlAnsiLimiter();
     this.historySupport = new OracleDbHistorySupport();
-
+    this.truncateTable = "truncate table %s cascade";
     dbIdentity.setIdType(IdType.SEQUENCE);
     dbIdentity.setSupportsSequence(true);
     dbIdentity.setSupportsIdentity(true);

src/main/java/io/ebean/config/dbplatform/postgres/PostgresPlatform.java

@@ -36,7 +36,7 @@ public class PostgresPlatform extends DatabasePlatform {
     this.clobDbType = Types.VARCHAR;
     this.nativeUuidType = true;
     this.columnAliasPrefix = null;
-
+    this.truncateTable = "truncate table %s cascade";
     this.dbEncrypt = new PostgresDbEncrypt();
     this.historySupport = new PostgresHistorySupport();
 

src/main/java/io/ebean/config/dbplatform/sqlite/SQLitePlatform.java

@@ -17,7 +17,7 @@ public class SQLitePlatform extends DatabasePlatform {
     this.dbIdentity.setSupportsGetGeneratedKeys(false);
     this.dbIdentity.setSupportsSequence(false);
     this.dbIdentity.setSelectLastInsertedIdTemplate("select last_insert_rowid()");
-
+    this.truncateTable = "delete from %s";
     this.booleanDbType = Types.INTEGER;
     this.likeClauseRaw = "like ?";
     this.likeClauseEscaped = "like ?";

src/main/java/io/ebeaninternal/server/core/DefaultServer.java

@@ -124,8 +124,10 @@ import javax.persistence.OptimisticLockException;
 import javax.persistence.PersistenceException;
 import javax.sql.DataSource;
 import java.sql.Connection;
+import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.time.Clock;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
@@ -639,6 +641,38 @@ public final class DefaultServer implements SpiServer, SpiEbeanServer {
     externalModification(evt);
   }
 
+  @Override
+  public void truncate(Class<?>... types) {
+    List<String> tableNames = new ArrayList<>();
+    for (Class<?> type : types) {
+      tableNames.add(getBeanDescriptor(type).getBaseTable());
+    }
+    truncate(tableNames.toArray(new String[0]));
+  }
+
+  @Override
+  public void truncate(String... tables) {
+    try (Connection connection = getDataSource().getConnection()) {
+      executeSql(connection, databasePlatform.truncateStatementBefore());
+      for (String table : tables) {
+        executeSql(connection, databasePlatform.truncateStatement(table));
+      }
+      executeSql(connection, databasePlatform.truncateStatementAfter());
+      connection.commit();
+    } catch(SQLException e) {
+      throw new PersistenceException("Error executing truncate", e);
+    }
+  }
+
+  private void executeSql(Connection connection, String sql) throws SQLException {
+    if (sql != null) {
+      try (PreparedStatement stmt = connection.prepareStatement(sql)) {
+        transactionManager.log().sql().debug(sql);
+        stmt.execute();
+      }
+    }
+  }
+
   /**
    * Clear the query execution statistics.
    */