* #67: Add Table#truncate() (#74)

* #67: Add Table#truncate()

Author: jakobbraun

doc/changes/changelog.md

@@ -1,5 +1,6 @@
 # Changes
 
+* [3.2.0](changes_3.2.0.md)
 * [3.1.1](changes_3.1.1.md)
 * [3.1.0](changes_3.1.0.md)
 * [3.0.0](changes_3.0.0.md)

doc/changes/changes_3.2.0.md

@@ -0,0 +1,11 @@
+# Test Database Builder 3.2.0, released 2021-03-XX
+
+Code name: Truncating tables
+
+## Summary
+
+In this release we added support for truncating tables.
+
+## Features
+
+* #67: Add Table#truncate()

pom.xml

@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.exasol</groupId>
     <artifactId>test-db-builder-java</artifactId>
-    <version>3.1.1</version>
+    <version>3.2.0</version>
     <name>Test Database Builder for Java</name>
     <description>pom.xml</description>
     <url>https://github.com/exasol/test-db-builder</url>

src/main/java/com/exasol/dbbuilder/dialects/AbstractImmediateDatabaseObjectWriter.java

@@ -58,6 +58,11 @@ public void write(final Table table) {
         writeToObject(table, builder.toString());
     }
 
+    @Override
+    public void truncate(final Table table) {
+        writeToObject(table, "TRUNCATE TABLE " + table.getFullyQualifiedName());
+    }
+
     /**
      * Get a quoted column name.
      * 

src/main/java/com/exasol/dbbuilder/dialects/DatabaseObjectWriter.java

@@ -30,6 +30,13 @@ public interface DatabaseObjectWriter {
      */
     void write(final Table table, final Stream<List<Object>> rows);
 
+    /**
+     * Truncate a table.
+     * 
+     * @param table table to truncate
+     */
+    void truncate(Table table);
+
     /**
      * Create a user in the database.
      *

src/main/java/com/exasol/dbbuilder/dialects/Table.java

@@ -73,6 +73,13 @@ public Table insert(final Object... values) {
         return this;
     }
 
+    /**
+     * Remove all rows from this table.
+     */
+    public void truncate() {
+        this.writer.truncate(this);
+    }
+
     /**
      * Insert multiple rows at once. Compared to inserting each row using {@link #insert(Object...)} this is a lot
      * faster.

src/test/java/com/exasol/dbbuilder/dialects/AbstractDatabaseObjectCreationAndDeletionIT.java

@@ -1,5 +1,6 @@
 package com.exasol.dbbuilder.dialects;
 
+import static org.hamcrest.CoreMatchers.equalTo;
 import static org.hamcrest.CoreMatchers.not;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.empty;
@@ -85,6 +86,23 @@ void testDropTable() {
         assertThat(table, not(existsInDatabase()));
     }
 
+    @Test
+    void testTruncateTable() throws SQLException {
+        final Schema schema = this.factory.createSchema("PARENT_SCHEMA_FOR_TRUNCATE_TABLE");
+        final Table table = schema.createTable("MY_TABLE", "COL1", "INTEGER").insert(1);
+        table.truncate();
+        assertThat(getTableSize(table), equalTo(0));
+    }
+
+    private int getTableSize(final Table table) throws SQLException {
+        try (final Statement statement = getAdminConnection().createStatement();
+                final ResultSet resultSet = statement
+                        .executeQuery("SELECT COUNT(*) FROM " + table.getFullyQualifiedName())) {
+            resultSet.next();
+            return resultSet.getInt(1);
+        }
+    }
+
     @Test
     protected void testCreateTableIsSqlInjectionSafe() {
         final Table table = this.factory.createSchema("INJECTION_TEST").createTable("INJECTION_TEST_TABLE " + QUOTES,