Hi,
1)
Update database table command will insert a new entry. But MODIFY will check if record already exist, if it exist then it will modify existing record else it will insert new record in db table.
For more details here is screenshot from F1 help -
INSERT - Inserting Data in Database Tables
Variants:
1. INSERT INTO dbtab [CLIENT SPECIFIED] VALUES wa.
INSERT INTO (dbtabname) [CLIENT SPECIFIED] VALUES wa.
2. INSERT dbtab [CLIENT SPECIFIED] FROM TABLE itab. oder
INSERT (dbtabname) [CLIENT SPECIFIED] FROM TABLE itab.
3. INSERT dbtab [CLIENT SPECIFIED]. oder
INSERT *dbtab [CLIENT SPECIFIED]. oder
INSERT (dbtabname) [CLIENT SPECIFIED] ... .
Effect Adds new records to a database table (see relational
database). You can specify the name of the database table
either directly in the program in the form dbtab or at runtime
as the contents of the field dbtabname. In either case, the
database table must be declared in the ABAP Dictionary. You
can only insert data using a view if the view refers to a
single table and has the maintenance status "No restriction"
in the ABAP Dictionary.
By default, data is only inserted in the current client.
However, if you use the CLIENT SPECIFIED addition, you can
switch off the automatic client handling. This enables you to
enter data for any client in a cross-client table, not just in
the client in which you are logged on. In this case, the
client field is treated like a normal field to which you can
assign a value in the work area.
MODIFY - Change a database table
Variants:
1. MODIFY dbtab. or
MODIFY *dbtab. or
MODIFY (dbtabname) ... ..
2. MODIFY dbtab FROM TABLE itab. or
MODIFY (dbtabname) FROM TABLE itab.
3. MODIFY dbtab VERSION vers. or
MODIFY *dbtab VERSION vers.
Effect Inserts new lines or updates existing lines in a database
table (s. relational database). If a line with the specified
primary key already exists, an UPDATE is executed. Otherwise,
an INSERT is performed. You can specify the name of the
database table either in the program itself in the form MODIFY
dbtab ... or at runtime as the contents of the field dbtabname
in the form MODIFY (dbtabname) ... . In both cases, the
database table must be defined in the ABAP Dictionary.
Normally, records are inserted or updated only in the current
client. Data can only be inserted or updated using a view, if
the view refers to a single table and was created in the ABAP
Dictionary with the maintenance status "No restriction".
MODIFY belongs to the Open SQL command set.
When the statement has been executed, the system field
SY-DBCNT contains the number of edited lines.
2)
When a document is changed it ll get posted in CDHDR table.
3)
I assume new records wouldnt be in CDHDR table.
Sri
Bluesky
