DialectCreator

Background and Use Cases

FineReport supports connecting to mainstream databases via JDBC. Although JDBC is highly standardized, different database vendors differ in connection protocols, usage patterns, and SQL syntax — differences referred to as "database dialects" in FanRuan development. Developers can use the DialectCreator interface to provide adaptation support for a target database, enabling it to work correctly within FineReport.

Interface Definition

package com.fr.stable.fun;

import com.fr.stable.fun.mark.Mutable;

public interface DialectCreator extends Mutable {
    String XML_TAG = "DialectCreator";
    int CURRENT_LEVEL = 1;

    /**
     * Returns the corresponding Dialect adapter class based on the data source driver info
     */
    Class<?> generate(UrlDriver driver);

    /**
     * Returns the corresponding Dialect adapter class based on the database connection
     */
    Class<?> generate(Connection connection);
}

The Dialect interface contains 80+ methods covering database-specific operations:

• Table/Schema initialization and retrieval
• Column type conversion
• SQL LIMIT/OFFSET generation
• Stored procedure handling
• Foreign key management
• Sequence/auto-increment generation
• Transaction control
• Unique constraint exception handling

AbstractDialect provides a simplified adapter wrapper; all Dialect interface methods delegate to the default implementations in DialectFactory. DefaultDialect extends AbstractDialect and implements all methods using the key-value pattern from DialectKeyConstants.

Supported Versions

Plugin Registration

Add the following node in plugin.xml:

<extra-core>
    <DialectCreator class="your class name"/>
</extra-core>

How It Works

All dialects are created by DialectFactory. During initialization, the factory instantiates DialectProviderImpl (which implements DialectProvider). The two methods getDialectFromExtraDriver and getDialectFromExtraMetadata retrieve dialect instances from plugins and return the corresponding dialect class.

Note: The DialectCreator#generate interface method must return null when no matching dialect is found.

Useful Links

• Demo: demo-dialect-creator