Baza danych

Ostrzeżenie

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SQL

Sponge zapewnia wygodną abstrakcję dla ustanowienia połączeń bazy danych które radzą sobie ze złożonościami ustanowienia wydajnego połączenia z JDBC URL.

While the SQL service supports any JDBC connector, the Forge implementation of Sponge only ships with the most common:

• MySQL

• Sqlite

• H2

Ostrzeżenie

Because Sqlite has many limitations, its usage is strongly discouraged except in cases where legacy compatibility is required. H2 is our recommended file-backed database implementation.

Sposób użycia

A data source can be accessed through the plugin’s service manager:

import org.spongepowered.api.Sponge;
import org.spongepowered.api.service.sql.SqlService;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.DataSource;

private SqlService sql;
public DataSource getDataSource(String jdbcUrl) throws SQLException {
    if (sql == null) {
        sql = Sponge.getServiceManager().provide(SqlService.class).get();
    }
    return sql.getDataSource(jdbcUrl);
}

// Later on
public void myMethodThatQueries() throws SQLException {
    String uri = "jdbc:h2:imalittledatabaseshortandstout.db";
    String sql = "SELECT * FROM test_tbl";

    try (Connection conn = getDataSource(uri).getConnection();
         PreparedStatement stmt = conn.prepareStatement(sql);
         ResultSet results = stmt.executeQuery()) {

        while (results.next()) {
            // ...
        }

    }

}

JDBC URLs should be obtained from SqlService#getConnectionUrlFromAlias(String), with an alias that matches one of the JDBC URL aliases listed in Sponge’s global configuration (config/sponge/global.conf) under the sponge.sql.aliases key.

The SQL service provides a pooled connection, so getting a connection from the returned DataSource is not expensive. Therefore, we recommended not keeping connections around, and closing them soon after use as shown above. Any PreparedStatement and ResultSet created should also be closed after use, with object.close() or, preferably, through a try-with-resources block.

NoSQL

Sponge does not currently provide any special abstraction over NoSQL databases (MongoDB etc.). Plugins that wish to use NoSQL databases must provide their own connectors.