An operator is either an action that must be performed on data,
or the output from a table or an index, when the access plan for an SQL
statement is executed.
The following operators can appear in the access plan graph:
- DELETE
- Deletes rows from a table.
- FETCH
- Fetches columns from a table using a specific record identifier.
- FILTER
- Filters data by applying one or more predicates to it.
- GRPBY
- Groups rows by common values of designated columns or functions, and
evaluates set functions.
- HSJOIN
- Represents a hash join, where two or more tables are hashed on the join
columns.
- INSERT
- Inserts rows into a table.
- IXAND
- ANDs together the row identifiers (RIDs) from two or more index
scans.
- IXSCAN
- Scans an index of a table with optional start/stop conditions, producing
an ordered stream of rows.
- MSJOIN
- Represents a merge join, where both outer and inner tables must be in
join-predicate order.
- NLJOIN
- Represents a nested loop join that accesses an inner table once for each
row of the outer table.
- RETURN
- Represents the return of data from the query to the user.
- RIDSCN
- Scans a list of row identifiers (RIDs) obtained from one or more
indexes.
- SORT
- Sorts rows in the order of specified columns, and optionally eliminates
duplicate entries.
- TBSCAN
- Retrieves rows by reading all required data directly from the data
pages.
- TEMP
- Stores data in a temporary table to be read back out (possibly multiple
times).
- TQUEUE
- Transfers table data between database agents.
- UNION
- Concatenates streams of rows from multiple tables.
- UNIQUE
- Eliminates rows with duplicate values, for specified columns.
- UPDATE
- Updates rows in a table.
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