ABAPMODIFY_ITAB_MULTIPLE - MODIFY ITAB MULTIPLE

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MODIFY itab, itab_lines

Short Reference

... itab FROM wa $[USING KEY keyname$]
         TRANSPORTING comp1 comp2 ... WHERE log_exp$|(cond_syntax).

Additions

1. ... WHERE log_exp

2. ... USING KEY keyname

3. ... WHERE (cond_syntax)

Effect

In this variant, the statement MODIFY assigns the content of the components comp1 comp2 ... of the work area wa specified after TRANSPORTING to all lines of the table itab that meet the condition after WHERE. wa is a functional operand position. The work area wa must be compatible with the line type of the internal table.

The addition TRANSPORTING has the same effect as changing individual lines. The addition WHERE can only be specified together with the addition TRANSPORTING.

Note

Outside of classes, an obsolete short form is possible where FROM wa can be omitted if the internal table has an identically named header line itab. The statement then uses the header line as the work area implicitly. Furthermore, USING KEY cannot be specified without FROM wa.

Addition 1

... WHERE log_exp

Effect

Static WHERE condition. All rows are processed for which the condition after WHERE is met. You can declare WHERE for all table categories.

After WHERE, you can declare a logical expression log_exp in which the first operand of each operation is a component of the internal table. You cannot specify a predicate function. The components of the internal table must be declared as individual operands and not as part of an expression. You cannot use parenthesized character-type data objects to declare a component dynamically here. The remaining operands of an operation can be any suitable individual operands or calculation expressions, but not components of the internal table. All logical expressions are possible except for the IS ASSIGNED, IS SUPPLIED, and obsolete IS REQUESTED predicates. The specified components can be of any data type. For evaluations, the relevant comparison rules apply.

When standard tables are accessed without a secondary key being specified, access is not optimized since all rows of the internal table are checked for the logical expression of the WHERE addition.

When a sorted key or a hash key is used, that is, when a sorted table, a hashed table, or a secondary table key is accessed, access is optimized in the following circumstances:

• If a sorted key is declared, the logical expression uses comparisons linked with AND with the relational operator = (or EQ) to include an initial part of the key that consists of at least one component. An AND operation with further comparisons is possible.
  
• If a hash key is declared, the logical condition uses comparisons linked with AND with the relational operator = (or EQ) to include all components of the key. An AND operation with further comparisons is possible
  
• The logical expression selects the same rows as a READ TABLE statement, in which the relevant components are specified as keys.
  

If the prerequisites for accessing a sorted or hashed table by means of the primary key are not met, optimization is not achieved and all rows of an internal table are checked as with standard tables.

,,When a secondary table key is accessed, that is, if one is specified in keyname after USING KEY, optimized execution is ensured, provided that the prerequisites above are met. Otherwise, a syntax error or exception occurs.

Notes

• When using a WHERE condition, note that the comparison rules for incompatible data types apply when incompatible data objects are compared, whereby the data types involved determine which operand is converted. In contrast, when the WITH TABLE KEY and WITH KEY additions of the READ statements are used, the content of the specified data objects is always converted into the data type of the columns before the comparison is made, which can lead to different results.
  
• When access is optimized, the WHERE condition is mapped internally to a READ statement with specification of the relevant key.
  
• Since the WHERE condition can only optimized if it produces the same results as a READ statement with the corresponding key specification, all operands of the logical expression should be compatible in pairs, if possible. This ensures that the result is not affected by the different behavior of the WHERE condition and the READ statement with a key specification.
  
• If a selection table is specified after IN as a logical expression, note that the expression for the initial table is always true and all rows are then processed.
  
  
  

Example

In the column col2 of the internal table itab, the MODIFY statement replaces every negative value with the number 0.

Addition 2

... USING KEY keyname

Effect

Using the USING KEY addition, a table key can be specified in keyname with which processing is carried out. The specified table key influences the sequence in which the table rows are accessed, and the evaluation of the remaining conditions.

If the primary table key is specified, processing behaves in the same way as when no key is explicitly specified. If a secondary table key is specified, the sequence in which the rows are accessed is as follows:

• Specification of a sorted key
  The rows are processed by ascending row number in the secondary table index
  
  
• Specification of a hash key
  The rows are processed in the sequence in which they were inserted into the table.
  

Note

In contrast to processing a hash table when a primary key is used, a preceding sort using the SORT statement has no influence on the processing sequence when a secondary hash key is specified.

Notes

• Unlike the processing of a hashed table when a primary key is used, a preceding sort using the statement SORT has no effect on the processing order when a secondary hash key is specified.

• If a secondary table key is specified, any WHERE condition must be optimizable. Otherwise a syntax error occurs, or an exception is raised.
  
  

Example

In the internal table itab, the MODIFY statement replaces the value in the column col1 with "_" if the column col2 contains the value 0. The WHERE condition is evaluated in an optimized way using the secondary key mkey.

Addition 3

... WHERE (cond_syntax)

Effect

Dynamic WHERE Condition cond_syntax can be specified as a character-like data object or standard table with character-like data type that, when the statement is executed, contains the syntax of a logical expression (in accordance with the rules of the static WHERE condition) or is initial.

The syntax in cond_syntax is, as in the ABAP Editor, not case-sensitive. When specifying an internal table, you can distribute the syntax over multiple rows. If cond_syntax is initial when the statement is executed, the logical expression is true. Invalid logical expressions trigger an exception from the class CX_SY_ITAB_DYN_LOOP.

The obsolete relational operators (><, =>, and =<) are not supported in cond_syntax.

Notes

• Of the calculation expressions, only arithmetic expressions are currently supported. String expressions and bit expressions are not supported. String functions and bit functions cannot be specified either.
  
• The dynamic WHERE conditions is not evaluated for a blank table for optimization reasons. Therefore, if an internal table is blank, and a logical expression has errors, no exception is raised.
  
  
  

Example

Like the example for static WHERE conditions, but with a condition for the column col2 that can be entered dynamically.

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