1  –  column-name

    Specifies the name of a column whose value you want to modify.

2  –  correlation-name

    Specifies a name you can use to identify the table or view in the
    predicate of the UPDATE statement. See the User_Supplied_Names
    HELP topic for more information about correlation names.

3  –  CURRENT OF cursor name

    If the WHERE clause uses CURRENT OF cursor-name, SQL modifies
    only the row on which the named cursor is positioned. The cursor
    named in an UPDATE statement must meet these conditions:

    o  The cursor must have been named previously in a DECLARE CURSOR
       statement or FOR statement.

    o  The cursor must be open.

    o  The cursor must be on a row.

    o  The FROM clause of the SELECT statement within the DECLARE
       CURSOR statement must refer to the table or view that is the
       target of the UPDATE statement.

4  –  DEFAULT

    SQL assigns the DEFAULT defined for the column or domain. If no
    DEFAULT is defined, then NULL is assumed.

    If the DEFAULT clause is used in an UPDATE statement then one of
    the following will be applied:

    o  If a DEFAULT attribute is present for the column then that
       value will be applied during UPDATE.

    o  Else if an AUTOMATIC attribute is present for the column then
       that value will be applied during UPDATE. This can only happen
       if the SET FLAGS 'AUTO_OVERRIDE' is used since during normal
       processing these columns are read-only.

    o  Otherwise a NULL will be applied during UPDATE.

5  –  INTO parameter

    Inserts the value specified to a specified parameter.

    The INTO parameter clause is optional in interactive SQL. In this
    case the returned values are displayed.

6  –  NULL

    Specifies a NULL keyword. SQL assigns a null value to columns for
    which you specify NULL. Any column assigned a null value must be
    defined to allow null values (defined in a CREATE or ALTER TABLE
    statement without the NOT NULL clause).

7  –  OPTIMIZE_AS

    Assigns a name to the query.

8  –  OPTIMIZE_FOR

    The OPTIMIZE FOR clause specifies the preferred optimizer
    strategy for statements that specify a select expression. The
    following options are available:

    o  FAST FIRST

       A query optimized for FAST FIRST returns data to the user as
       quickly as possible, even at the expense of total throughput.

       If a query can be cancelled prematurely, you should specify
       FAST FIRST optimization. A good candidate for FAST FIRST
       optimization is an interactive application that displays
       groups of records to the user, where the user has the option
       of aborting the query after the first few screens. For
       example, singleton SELECT statements default to FAST FIRST
       optimization.

       If optimization strategy is not explicitly set, FAST FIRST is
       the default.

    o  TOTAL TIME

       If your application runs in batch, accesses all the records in
       the query, and performs updates or writes a report, you should
       specify TOTAL TIME optimization. Most queries benefit from
       TOTAL TIME optimization.

    o  SEQUENTIAL ACCESS

       Forces the use of sequential access. This is particularly
       valuable for tables that use the strict partitioning
       functionality.

9  –  OPTIMIZE_USING

    Explicitly names the query outline to be used with the UPDATE
    statement even if the outline ID for the query and for the
    outline are different.

10  –  OPTIMIZE_WITH

    Selects one of three optimzation controls: DEFAULT (as used by
    previous versions of Rdb), AGGRESSIVE (assumes smaller numbers of
    rows will be selected), and SAMPLED (which uses literals in the
    query to perform preliminary estimation on indices).

11  –  predicate

    If the WHERE clause includes a predicate, all the rows of the
    target table for which the predicate is true are modified.

    The columns named in the predicate must be columns of the target
    table or view. The target table cannot be named in a column
    select expression within the predicate.

    See the Predicates HELP topic for more information on predicates.

12  –  RETURNING value expr

    Returns the value of the column specified in the value
    expression. If DBKEY is specified, SQL returns the database key
    (dbkey) of the row being updated. When the DBKEY value is valid,
    subsequent queries can use the DBKEY value to access the row
    directly.

    The RETURNING DBKEY clause is not valid in an UPDATE statement
    used to assign values to the segments in a column of the LIST OF
    BYTE VARYING data type.

    Only one row can be updated when you specify the RETURNING
    clause.

13  –  SET

    Specifies which columns in the table or view get what values. For
    each column you want to modify, you must specify the column name
    and either a value expression, the NULL keyword, or the DEFAULT
    keyword. SQL assigns the value following the equal sign to the
    column that precedes the equal sign.

14  –  table-name

    Specifies the name of the target table that you want to modify.

15  –  value-expr

    Specifies the new value for the modified column. Columns named in
    the value expression must be columns of the table or view named
    after the UPDATE keyword. The values can be specified through
    parameters, qualified parameters, column select expressions,
    value expressions, or the default values.

16  –  view-name

    Specifies the name of the target view that you want to modify.

17  –  WHERE

    Specifies the rows of the target table or view that will be
    modified according to the values indicated in the SET clause.
    If you omit the WHERE clause, SQL modifies all rows of the target
    table or view. You can specify either a predicate or a cursor
    name in the WHERE clause.