package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.MSSQLDatabase;

 import liquibase.exception.ValidationErrors;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGenerator;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.FindForeignKeyConstraintsStatement;

 public class FindForeignKeyConstraintsGeneratorMSSQL extends AbstractSqlGenerator<FindForeignKeyConstraintsStatement> {

     @Override

     public int getPriority() {

         return PRIORITY_DATABASE;

     }

     @Override

     public boolean supports(FindForeignKeyConstraintsStatement statement, Database database) {

         return database instanceof MSSQLDatabase;

     }

     public ValidationErrors validate(FindForeignKeyConstraintsStatement findForeignKeyConstraintsStatement,

             Database database, SqlGeneratorChain sqlGeneratorChain) {

         ValidationErrors validationErrors = new ValidationErrors();

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

         return validationErrors;

     }

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

             SqlGeneratorChain sqlGeneratorChain) {

         StringBuilder sb = new StringBuilder();

         sb.append("SELECT TOP 1");

         sb.append("OBJECT_NAME(f.parent_object_id) AS ")

                 .append(FindForeignKeyConstraintsStatement.RESULT_COLUMN_BASE_TABLE_NAME).append(", ");

         sb.append("COL_NAME(fc.parent_object_id, fc.parent_column_id) AS ")

                 .append(FindForeignKeyConstraintsStatement.RESULT_COLUMN_BASE_TABLE_COLUMN_NAME).append(", ");

         sb.append("OBJECT_NAME (f.referenced_object_id) AS ")

                 .append(FindForeignKeyConstraintsStatement.RESULT_COLUMN_FOREIGN_TABLE_NAME).append(", ");

         sb.append("COL_NAME(fc.referenced_object_id, fc.referenced_column_id) AS ")

                 .append(FindForeignKeyConstraintsStatement.RESULT_COLUMN_FOREIGN_COLUMN_NAME).append(",");

         sb.append("f.name AS ").append(FindForeignKeyConstraintsStatement.RESULT_COLUMN_CONSTRAINT_NAME).append(" ");

         sb.append("FROM sys.foreign_keys AS f ");

         sb.append("INNER JOIN sys.foreign_key_columns AS fc ");

         sb.append("ON f.OBJECT_ID = fc.constraint_object_id ");

         sb.append("WHERE OBJECT_NAME(f.parent_object_id) = '").append(statement.getBaseTableName()).append("'");

         return new Sql[] { new UnparsedSql(sb.toString()) };

     }

 }