Optionally allow use of stored procedures for MySql to drop columns in db migration

ebean-ddl-generator/src/test/java/io/ebeaninternal/dbmigration/MysqlGenerateMigrationTest.java

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+package io.ebeaninternal.dbmigration;
+
+import io.ebean.Database;
+import io.ebean.DatabaseFactory;
+import io.ebean.annotation.Platform;
+import io.ebean.config.DatabaseConfig;
+import io.ebean.config.PlatformConfig;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Class to test the alternative drop behaviour using stored procedures for MySql databases .
+ *
+ * @author Jonas Pöhler, FOCONIS AG
+ */
+public class MysqlGenerateMigrationTest {
+
+  @Test
+  public void testMysqlStoredProcedures() throws Exception {
+    DefaultDbMigration migration = new DefaultDbMigration();
+    migration.setIncludeIndex(true);
+    // We use src/test/resources as output directory (so we see in GIT if files will change)
+    migration.setPathToResources("src/test/resources");
+
+    migration.addPlatform(Platform.MYSQL, "mysql");
+
+    final PlatformConfig platformConfig = new PlatformConfig();
+    platformConfig.setUseMigrationStoredProcedures(true);
+
+    DatabaseConfig config = new DatabaseConfig();
+    config.setName("migrationtest");
+    config.loadFromProperties();
+    config.setPlatformConfig(platformConfig);
+    config.setRegister(false);
+    config.setDefaultServer(false);
+    config.getProperties().put("ebean.migration.migrationPath", "db/migration/mysql");
+
+    config.setPackages(Arrays.asList("misc.migration.mysql_v1_0"));
+    Database server = DatabaseFactory.create(config);
+    migration.setServer(server);
+    migration.setMigrationPath("mysql/procedures");
+
+    // First, we clean up the output-directory
+    assertThat(migration.migrationDirectory().getAbsolutePath()).contains("procedures");
+    Files.walk(migration.migrationDirectory().toPath())
+      .filter(Files::isRegularFile)
+      .map(Path::toFile).forEach(File::delete);
+
+    // then we generate migration scripts for v1_0
+    assertThat(migration.generateMigration()).isEqualTo("1.0__initial");
+
+    config.setPackages(Arrays.asList("misc.migration.mysql_v1_1"));
+    server.shutdown();
+    server = DatabaseFactory.create(config);
+    migration.setServer(server);
+    migration.setMigrationPath("mysql/procedures");
+    assertThat(migration.generateMigration()).isEqualTo("1.1");
+
+    System.setProperty("ddl.migration.pendingDropsFor", "1.1");
+    assertThat(migration.generateMigration()).isEqualTo("1.2__dropsFor_1.1");
+
+    final Path sqlFile = migration.migrationDirectory().toPath()
+      .resolve("mysql/1.2__dropsFor_1.1.sql");
+
+    assertThat(sqlFile).isNotEmptyFile();
+    assertThat(Files.readAllLines(sqlFile, StandardCharsets.UTF_8))
+      .contains("CALL usp_ebean_drop_column('migtest_e_basic', 'status2');")
+      .contains("CALL usp_ebean_drop_column('migtest_e_basic', 'description');");
+
+  }
+}

ebean-ddl-generator/src/test/java/misc/migration/mysql_v1_0/EBasic.java

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+package misc.migration.mysql_v1_0;
+
+import io.ebean.annotation.DbDefault;
+import io.ebean.annotation.EnumValue;
+import io.ebean.annotation.NotNull;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.validation.constraints.Size;
+
+@Entity
+@Table(name = "migtest_e_basic")
+public class EBasic {
+
+  public enum Status {
+    @EnumValue("N")
+    NEW,
+
+    @EnumValue("A")
+    ACTIVE,
+
+    @EnumValue("I")
+    INACTIVE,
+  }
+
+  @Id
+  Integer id;
+
+  Status status;
+
+  @DbDefault("N")
+  @NotNull
+  Status status2;
+
+  @Size(max=127)
+  String name;
+
+  @Size(max=127)
+  String description;
+
+  public EBasic() {
+
+  }
+
+  public EBasic(String name) {
+    this.name = name;
+  }
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public Status getStatus() {
+    return status;
+  }
+
+  public void setStatus(Status status) {
+    this.status = status;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public String getDescription() {
+    return description;
+  }
+
+  public void setDescription(String description) {
+    this.description = description;
+  }
+
+  public Status getStatus2() {
+    return status2;
+  }
+
+  public void setStatus2(final Status status2) {
+    this.status2 = status2;
+  }
+}

ebean-ddl-generator/src/test/java/misc/migration/mysql_v1_1/EBasic.java

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+package misc.migration.mysql_v1_1;
+
+import io.ebean.annotation.EnumValue;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.validation.constraints.Size;
+
+@Entity
+@Table(name = "migtest_e_basic")
+public class EBasic {
+
+  public enum Status {
+    @EnumValue("N")
+    NEW,
+
+    @EnumValue("A")
+    ACTIVE,
+
+    @EnumValue("I")
+    INACTIVE,
+  }
+
+  @Id
+  Integer id;
+
+  Status status;
+
+  @Size(max=127)
+  String name;
+
+  public EBasic() {
+
+  }
+
+  public EBasic(String name) {
+    this.name = name;
+  }
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public Status getStatus() {
+    return status;
+  }
+
+  public void setStatus(Status status) {
+    this.status = status;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+}

ebean-ddl-generator/src/test/resources/mysql/procedures/model/1.0__initial.model.xml

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<migration xmlns="http://ebean-orm.github.io/xml/ns/dbmigration">
+    <changeSet type="apply">
+        <createTable name="migtest_e_basic" pkName="pk_migtest_e_basic">
+            <column name="id" type="integer" primaryKey="true"/>
+            <column name="status" type="varchar(1)" checkConstraint="check ( status in ('N','A','I'))" checkConstraintName="ck_migtest_e_basic_status"/>
+            <column name="status2" type="varchar(1)" defaultValue="'N'" notnull="true" checkConstraint="check ( status2 in ('N','A','I'))" checkConstraintName="ck_migtest_e_basic_status2"/>
+            <column name="name" type="varchar(127)"/>
+            <column name="description" type="varchar(127)"/>
+        </createTable>
+    </changeSet>
+</migration>

ebean-ddl-generator/src/test/resources/mysql/procedures/model/1.1.model.xml

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<migration xmlns="http://ebean-orm.github.io/xml/ns/dbmigration">
+    <changeSet type="pendingDrops">
+        <dropColumn columnName="status2" tableName="migtest_e_basic"/>
+        <dropColumn columnName="description" tableName="migtest_e_basic"/>
+    </changeSet>
+</migration>

ebean-ddl-generator/src/test/resources/mysql/procedures/model/1.2__dropsFor_1.1.model.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<migration xmlns="http://ebean-orm.github.io/xml/ns/dbmigration">
+    <changeSet type="apply" dropsFor="1.1">
+        <dropColumn columnName="status2" tableName="migtest_e_basic"/>
+        <dropColumn columnName="description" tableName="migtest_e_basic"/>
+    </changeSet>
+</migration>

ebean-ddl-generator/src/test/resources/mysql/procedures/mysql/1.0__initial.sql

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+-- Migrationscripts for ebean unittest
+-- apply changes
+create table migtest_e_basic (
+  id                            integer auto_increment not null,
+  status                        varchar(1),
+  status2                       varchar(1) default 'N' not null,
+  name                          varchar(127),
+  description                   varchar(127),
+  constraint pk_migtest_e_basic primary key (id)
+);
+

ebean-ddl-generator/src/test/resources/mysql/procedures/mysql/1.2__dropsFor_1.1.sql

@@ -0,0 +1,6 @@
+-- Migrationscripts for ebean unittest
+-- apply changes
+CALL usp_ebean_drop_column('migtest_e_basic', 'status2');
+
+CALL usp_ebean_drop_column('migtest_e_basic', 'description');
+

ebean-ddl-generator/src/test/resources/mysql/procedures/mysql/I__create_procs.sql

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+-- Inital script to create stored procedures etc for mysql platform
+DROP PROCEDURE IF EXISTS usp_ebean_drop_foreign_keys;
+
+delimiter $$
+--
+-- PROCEDURE: usp_ebean_drop_foreign_keys TABLE, COLUMN
+-- deletes all constraints and foreign keys referring to TABLE.COLUMN
+--
+CREATE PROCEDURE usp_ebean_drop_foreign_keys(IN p_table_name VARCHAR(255), IN p_column_name VARCHAR(255))
+BEGIN
+DECLARE done INT DEFAULT FALSE;
+DECLARE c_fk_name CHAR(255);
+DECLARE curs CURSOR FOR SELECT CONSTRAINT_NAME from information_schema.KEY_COLUMN_USAGE
+WHERE TABLE_SCHEMA = DATABASE() and TABLE_NAME = p_table_name and COLUMN_NAME = p_column_name
+AND REFERENCED_TABLE_NAME IS NOT NULL;
+DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
+
+OPEN curs;
+
+read_loop: LOOP
+FETCH curs INTO c_fk_name;
+IF done THEN
+LEAVE read_loop;
+END IF;
+SET @sql = CONCAT('ALTER TABLE ', p_table_name, ' DROP FOREIGN KEY ', c_fk_name);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+END LOOP;
+
+CLOSE curs;
+END
+$$
+
+DROP PROCEDURE IF EXISTS usp_ebean_drop_column;
+
+delimiter $$
+--
+-- PROCEDURE: usp_ebean_drop_column TABLE, COLUMN
+-- deletes the column and ensures that all indices and constraints are dropped first
+--
+CREATE PROCEDURE usp_ebean_drop_column(IN p_table_name VARCHAR(255), IN p_column_name VARCHAR(255))
+BEGIN
+CALL usp_ebean_drop_foreign_keys(p_table_name, p_column_name);
+SET @sql = CONCAT('ALTER TABLE ', p_table_name, ' DROP COLUMN ', p_column_name);
+PREPARE stmt FROM @sql;
+EXECUTE stmt;
+END
+$$

ebean-ddl-generator/src/test/resources/mysql/procedures/mysql/idx_mysql.migrations

@@ -0,0 +1,4 @@
+1835064798,     I__create_procs.sql
+1968521526,     1.0__initial.sql
+-728933533,     1.2__dropsFor_1.1.sql
+