package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.CacheDatabase;

 import liquibase.database.core.DB2Database;

 import liquibase.database.core.DerbyDatabase;

 import liquibase.database.core.FirebirdDatabase;

 import liquibase.database.core.H2Database;

 import liquibase.database.core.HsqlDatabase;

 import liquibase.database.core.InformixDatabase;

 import liquibase.database.core.MSSQLDatabase;

 import liquibase.database.core.SybaseASADatabase;

 import liquibase.exception.ValidationErrors;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.CreateViewStatement;

 public class CreateViewGenerator extends AbstractSqlGenerator<CreateViewStatement> {

     @Override

     public ValidationErrors validate(CreateViewStatement createViewStatement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         ValidationErrors validationErrors = new ValidationErrors();

         validationErrors.checkRequiredField("viewName", createViewStatement.getViewName());

         validationErrors.checkRequiredField("selectQuery", createViewStatement.getSelectQuery());

         if (createViewStatement.isReplaceIfExists()) {

             validationErrors.checkDisallowedField("replaceIfExists", createViewStatement.isReplaceIfExists(), database,

                     HsqlDatabase.class, H2Database.class, DB2Database.class, CacheDatabase.class, MSSQLDatabase.class,

                     DerbyDatabase.class, SybaseASADatabase.class, InformixDatabase.class);

         }

         return validationErrors;

     }

     @Override

     public Sql[] generateSql(CreateViewStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {

         String createClause;

         if (database instanceof FirebirdDatabase) {

             if (statement.isReplaceIfExists()) {

                 createClause = "RECREATE VIEW";

             } else {

                 createClause = "RECREATE VIEW";

             }

         } else if (database instanceof SybaseASADatabase

                 && statement.getSelectQuery().toLowerCase().startsWith("create view")) {

             // Sybase ASA saves view definitions with header.

             return new Sql[] { new UnparsedSql(statement.getSelectQuery()) };

         } else {

             createClause = "CREATE " + (statement.isReplaceIfExists() ? "OR REPLACE " : "") + "VIEW";

         }

         return new Sql[] { new UnparsedSql(createClause + " "

                 + database.escapeViewName(statement.getSchemaName(), statement.getViewName()) + " AS "

                 + statement.getSelectQuery()) };

     }

 }