When you set up Readers, you may want to limit the records that should be read.
Some Readers allow to read more files at the same time. In these Readers, you can define the records that should be read for each input file separately and for all of the input files in total.
In these Readers, you can define the Number of skipped records and/or Max number of records attributes. The former attribute specifies how many records should be skipped, the latter defines how many records should be read. Remember that these records are skipped and/or read continuously throughout all input files. These records are skipped and/or read independently on the values of the two similar attributes mentioned below.
In these components you can also specify how many records should be skipped and/or read from each input file. To do this, set up the following two attributes: Number of skipped records per source and/or Max number of records per source.
Thus, total number of records that are skipped equals to Number of skipped records per source multiplicated by the number of source files plus Number of skipped records.
And total number of records that are read equals to Max number of records per source multiplicated by the number of source files plus Max number of records.
The Readers that allow limiting the records for both individual input file and all input files in total are the following:
CSVReader
XLSDataReader
DBFDataReader
MultiLevelReader (Commercial Component)
Unlike the components mentioned above, CloudConnectDataReader only allows you to limit the total number of records from all input files:
CloudConnectDataReader only allows you to limit the total number of records by using the Number of skipped records and/or Max number of records attributes as shown in previous components.
The following two Readers allow you to limit the total number of records by using the Number of skipped mappings and/or Max number of mappings attributes. What is called mapping here, is a subtree which should be mapped and sent out through the output ports.
XMLExtract. In addition to the
mentioned above, this component also allows to use the
skipRows and/or the
numRecords attributes of individual XML
elements.
XMLXPathReader. In addition to the mentioned above, this component allows to use XPath language to limit the number of mapped XML structures.
The following Readers allow limiting the numbers in a different way:
JMSReader allows you to limit the
number of messages that are received and processed by using the
Max msg count attribute and/or the
false return value of
endOfInput() method of the component
interface.
DBInputTable. Also this component can use the SQL query or the Query URL attribute to limit the number of records.
The following Readers do not allow limiting the number of records that should be read (they read them all):
LDAPReader
ParallelReader (Commercial Component)