Specifies the following behavior:

    o  The same dialect rules as SQL92 are in effect minus reserved
       word checking and the DATE ANSI format.

    o  The ORACLE LEVEL1 dialect allows the use of aliases to
       reference (or link) to tables in data manipulation statements
       like SELECT, DELETE, INSERT, and UPDATE. For example:

       SQL> ATTACH 'ALIAS pers_alias FILENAME mf_personnel';
       SQL> SET DIALECT 'ORACLE LEVEL1';
       SQL> SELECT * FROM employees@pers_alias
       cont> WHERE employee_id = '00164';
        EMPLOYEE_ID   LAST_NAME        FIRST_NAME   MIDDLE_INITIAL
          ADDRESS_DATA_1              ADDRESS_DATA_2         CITY
             STATE   POSTAL_CODE   SEX    BIRTHDAY      STATUS_CODE
        00164         Toliver          Alvin        A
          146 Parnell Place                                  Chocorua
             NH      03817         M      28-Mar-1947   1

       1 row selected

       Alias references are only allowed on the table name and not on
       column names. You cannot put a space between the table name,
       the at (@)  sign, and the alias name.

       If you specify a schema name when referencing an Oracle Rdb
       database, the schema name is ignored unless the multischema
       attribute is on.

    o  The following basic predicate for inequality comparisons is
       supported:

          !=

       The != basic predicate requires that the ORACLE LEVEL1 dialect
       be set to avoid confusion with the interactive SQL comment
       character.

    o  When using dynamic SQL, the client application can specify a
       synonym for the parameter marker (?).  For example, :name, :1,
       :2, and so on.

    o  The string concatenation operator and the CONCAT function
       treat nulls as zero-length strings.

    o  The default date format is DATE VMS which is capable of doing
       arithmetic in the ORACLE LEVEL1 dialect only. Addition and
       subtraction can be done with numeric data types that are
       implicitly cast to the INTERVAL DAY data type. Fractions are
       rounded to the nearest whole integer.

    o  Zero length strings are null. When using an Oracle RDBMS
       database, a VARCHAR of zero length is considered null. While
       the Oracle Rdb ORACLE LEVEL1 dialect does not remove zero
       length strings from the database, it does make them difficult
       to create. The following rules are in effect:

       -  Empty literal strings (for example, '') are considered
          literal nulls.

       -  Any function that encounters a zero length string returns
          a null in its place. This includes stored and external
          functions returning a VARCHAR data type regardless of the
          dialect under which they were compiled. It also includes
          the TRIM and SUBSTRING built-in functions.

       -  Parameters with the VARCHAR data type and a length of zero
          are treated as null.

       The best way to avoid zero length strings from being seen
       by an Oracle RDBMS application is to only use views compiled
       under the ORACLE dialects and to modify tables with VARCHAR
       columns to remove zero length strings. The following example
       shows how to remove zero length strings from a VARCHAR column
       in a table:

       SQL> UPDATE tab1 SET col1 = NULL WHERE CHARACTER_LENGTH(col1) = 0;

       If modifying the table is not possible or if a view compiled
       in another dialect containing VARCHAR functions must be used,
       then create a new view under the ORACLE dialect referring to
       that table or view to avoid the zero length VARCHAR string.
       The following example shows how to avoid selecting zero length
       strings from a VARCHAR column in a table or non-Oracle dialect
       view:

       SQL> SET DIALECT 'ORACLE LEVEL1';
       SQL> CREATE VIEW view1 (col1, col2)
       cont>    AS SELECT SUBSTRING(col1 FROM 1 FOR 2000), col2 FROM tab1;

       The Oracle Rdb optimizer is more efficient if data is selected
       without the use of functions. Therefore, the previous example
       is best used only if you suspect zero length strings have been
       inserted into the table and it is necessary to avoid them.

    o  The ROWNUM keyword is allowed in select expressions and limits
       the number of rows returned in the query. The following
       example limits the number of rows returned by the SELECT
       statement to 9 rows:

       SQL> ATTACH 'FILENAME mf_personnel';
       SQL> SET DIALECT 'ORACLE LEVEL1';
       SQL> SELECT last_name FROM EMPLOYEES WHERE ROWNUM < 10;
        LAST_NAME
        Toliver
        Smith
        Dietrich
        Kilpatrick
        Nash
        Gray
        Wood
        D'Amico
        Peters
       9 rows selected

       Conditions testing for ROWNUM values greater than or equal to
       a positive integer are always false and, therefore, return no
       rows. For example:

       SQL> SELECT last_name FROM EMPLOYEES WHERE ROWNUM > 10;
       0 rows selected
       SQL> SELECT last_name FROM EMPLOYEES WHERE ROWNUM = 10;
       0 rows selected