MySQLSchema.java

/*-
 * ========================LICENSE_START=================================
 * flyway-mysql
 * ========================================================================
 * Copyright (C) 2010 - 2026 Red Gate Software Ltd
 * ========================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * =========================LICENSE_END==================================
 */
package org.flywaydb.database.mysql;

import org.flywaydb.core.internal.database.base.Schema;
import org.flywaydb.core.internal.database.base.Table;
import org.flywaydb.core.internal.jdbc.JdbcTemplate;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

public class MySQLSchema extends Schema<MySQLDatabase, MySQLTable> {

    MySQLSchema(final JdbcTemplate jdbcTemplate, final MySQLDatabase database, final String name) {
        super(jdbcTemplate, database, name);
    }

    @Override
    protected boolean doExists() throws SQLException {
        return jdbcTemplate.queryForInt("SELECT COUNT(1) FROM information_schema.schemata WHERE schema_name=? LIMIT 1",
            name) > 0;
    }

    @Override
    protected boolean doEmpty() throws SQLException {
        final List<String> params = new ArrayList<>(Arrays.asList(name, name, name, name, name));
        if (database.eventSchedulerQueryable) {
            params.add(name);
        }

        return jdbcTemplate.queryForInt("SELECT SUM(found) FROM ("
            + "(SELECT 1 as found FROM information_schema.tables WHERE table_schema=?) UNION ALL "
            + "(SELECT 1 as found FROM information_schema.views WHERE table_schema=? LIMIT 1) UNION ALL "
            + "(SELECT 1 as found FROM information_schema.table_constraints WHERE table_schema=? LIMIT 1) UNION ALL "
            + "(SELECT 1 as found FROM information_schema.triggers WHERE event_object_schema=?  LIMIT 1) UNION ALL "
            + "(SELECT 1 as found FROM information_schema.routines WHERE routine_schema=? LIMIT 1)"
            // #2410 Unlike MySQL, MariaDB 10.0 and newer don't allow the events table to be queried
            // when the event scheduled is DISABLED or in some rare cases OFF
            + (database.eventSchedulerQueryable
            ? " UNION ALL (SELECT 1 as found FROM information_schema.events WHERE event_schema=? LIMIT 1)"
            : "")
            + ") as all_found", params.toArray(String[]::new)) == 0;
    }

    @Override
    protected void doCreate() throws SQLException {
        jdbcTemplate.execute("CREATE SCHEMA " + database.quote(name));
    }

    @Override
    protected void doDrop() throws SQLException {
        jdbcTemplate.execute("DROP SCHEMA " + database.quote(name));
    }

    @Override
    protected void doClean() throws SQLException {
        if (database.eventSchedulerQueryable) {
            for (final String statement : cleanEvents()) {
                jdbcTemplate.execute(statement);
            }
        }

        for (final String statement : cleanRoutines()) {
            jdbcTemplate.execute(statement);
        }

        for (final String statement : cleanViews()) {
            jdbcTemplate.execute(statement);
        }

        jdbcTemplate.execute("SET FOREIGN_KEY_CHECKS = 0");
        for (final Table table : allTables()) {
            table.drop();
        }
        jdbcTemplate.execute("SET FOREIGN_KEY_CHECKS = 1");

        // MariaDB 10.3 and newer only
        for (final String statement : cleanSequences()) {
            jdbcTemplate.execute(statement);
        }
    }

    private List<String> cleanEvents() throws SQLException {
        final List<String> eventNames = jdbcTemplate.queryForStringList(
            "SELECT event_name FROM information_schema.events WHERE event_schema=?",
            name);

        final List<String> statements = new ArrayList<>();
        for (final String eventName : eventNames) {
            statements.add("DROP EVENT " + database.quote(name, eventName));
        }
        return statements;
    }

    private List<String> cleanRoutines() throws SQLException {
        final List<Map<String, String>> routineNames = jdbcTemplate.queryForList(
            "SELECT routine_name as 'N', routine_type as 'T' FROM information_schema.routines WHERE routine_schema=?",
            name);

        final List<String> statements = new ArrayList<>();
        for (final Map<String, String> row : routineNames) {
            final String routineName = row.get("N");
            final String routineType = row.get("T");
            statements.add("DROP " + routineType + " " + database.quote(name, routineName));
        }
        return statements;
    }

    private List<String> cleanViews() throws SQLException {
        final List<String> viewNames = jdbcTemplate.queryForStringList(
            "SELECT table_name FROM information_schema.views WHERE table_schema=?",
            name);

        final List<String> statements = new ArrayList<>();
        for (final String viewName : viewNames) {
            statements.add("DROP VIEW " + database.quote(name, viewName));
        }
        return statements;
    }

    private List<String> cleanSequences() throws SQLException {
        final List<String> names = jdbcTemplate.queryForStringList(
            "SELECT table_name FROM information_schema.tables WHERE table_schema=?" + " AND table_type='SEQUENCE'",
            name);

        final List<String> statements = new ArrayList<>();
        for (final String name : names) {
            statements.add("DROP SEQUENCE " + database.quote(this.name, name));
        }
        return statements;
    }

    @Override
    protected MySQLTable[] doAllTables() throws SQLException {
        final List<String> tableNames = jdbcTemplate.queryForStringList(
            "SELECT table_name FROM information_schema.tables WHERE table_schema=?"
                + " AND table_type IN ('BASE TABLE', 'SYSTEM VERSIONED')",
            name);

        final MySQLTable[] tables = new MySQLTable[tableNames.size()];
        for (int i = 0; i < tableNames.size(); i++) {
            tables[i] = new MySQLTable(jdbcTemplate, database, this, tableNames.get(i));
        }
        return tables;
    }

    @Override
    public Table getTable(final String tableName) {
        return new MySQLTable(jdbcTemplate, database, this, tableName);
    }
}