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/*
This file is part of Subsonic.
Subsonic is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Subsonic is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Subsonic. If not, see <http://www.gnu.org/licenses/>.
Copyright 2009 (C) Sindre Mehus
*/
package net.sourceforge.subsonic.backend.dao.schema;
import org.springframework.jdbc.core.JdbcTemplate;
/**
* Used for creating and evolving the database schema.
*
* @author Sindre Mehus
*/
public abstract class Schema {
/**
* Executes this schema.
* @param template The JDBC template to use.
*/
public abstract void execute(JdbcTemplate template);
/**
* Returns whether the given table exists.
* @param template The JDBC template to use.
* @param table The table in question.
* @return Whether the table exists.
*/
protected boolean tableExists(JdbcTemplate template, String table) {
try {
template.execute("select 1 from " + table);
} catch (Exception x) {
return false;
}
return true;
}
/**
* Returns whether the given column in the given table exists.
* @param template The JDBC template to use.
* @param column The column in question.
* @param table The table in question.
* @return Whether the column exists.
*/
protected boolean columnExists(JdbcTemplate template, String column, String table) {
try {
template.execute("select " + column + " from " + table + " where 1 = 0");
} catch (Exception x) {
return false;
}
return true;
}
}
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