package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.MaxDBDatabase;

 import liquibase.database.core.MySQLDatabase;

 import liquibase.database.core.SQLiteDatabase;

 import liquibase.database.core.SybaseASADatabase;

 import liquibase.exception.ValidationErrors;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGenerator;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.DropForeignKeyConstraintStatement;

 public class DropForeignKeyConstraintGenerator extends AbstractSqlGenerator<DropForeignKeyConstraintStatement> {

     @Override

     public boolean supports(DropForeignKeyConstraintStatement statement, Database database) {

         return (!(database instanceof SQLiteDatabase));

     }

     public ValidationErrors validate(DropForeignKeyConstraintStatement dropForeignKeyConstraintStatement,

             Database database, SqlGeneratorChain sqlGeneratorChain) {

         ValidationErrors validationErrors = new ValidationErrors();

         validationErrors.checkRequiredField("baseTableName", dropForeignKeyConstraintStatement.getBaseTableName());

         validationErrors.checkRequiredField("constraintName", dropForeignKeyConstraintStatement.getConstraintName());

         return validationErrors;

     }

     public Sql[] generateSql(DropForeignKeyConstraintStatement statement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         if (database instanceof MySQLDatabase || database instanceof MaxDBDatabase

                 || database instanceof SybaseASADatabase) {

             return new Sql[] { new UnparsedSql("ALTER TABLE "

                     + database.escapeTableName(statement.getBaseTableSchemaName(), statement.getBaseTableName())

                     + " DROP FOREIGN KEY " + database.escapeConstraintName(statement.getConstraintName())) };

         } else {

             return new Sql[] { new UnparsedSql("ALTER TABLE "

                     + database.escapeTableName(statement.getBaseTableSchemaName(), statement.getBaseTableName())

                     + " DROP CONSTRAINT " + database.escapeConstraintName(statement.getConstraintName())) };

         }

     }

 }