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Component family
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Big Data/MemSQL
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Function
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tMemSQLRow is the specific
component for this database query. It executes the MemSQL query
stated in the specified database. The row suffix means the component
implements a flow in the job design although it does not provide
output.
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Purpose
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Depending on the nature of the query and the database, tMemSQLRow acts on the actual database
structure or on the data (although without handling data). The
SQLBuilder tool helps you write easily your SQL statements.
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Basic settings
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Property type
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Either Built-in or
Repository.
Since version 5.6, both the Built-In mode and the Repository mode are
available in any of the Talend solutions.
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Built-in: No property data stored
centrally.
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Repository: Select the repository
file in which the properties are stored. The fields that follow are
completed automatically using the data retrieved.
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Use an existing connection
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Select this check box and in the Component List click the
relevant connection component to reuse the connection details you already defined.
Note
When a Job contains the parent Job and the child Job, if you need to share an existing
connection between the two levels, for example, to share the connection created by the
parent Job with the child Job, you have to:
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In the parent level, register the database connection to be shared in the
Basic settings view of the connection
component which creates that very database connection.
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In the child level, use a dedicated connection component to read that
registered database connection.
For an example about how to share a database connection across Job levels, see
Talend Studio User
Guide.
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Host
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Enter the location of the server of the MemSQL database to be
used.
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Port
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Enter the listening port number of the database server.
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Database
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Enter the name of the MemSQL database to be used.
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Username and
Password
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Enter the user authentication data for connecting to the database
to be used.
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Table Name
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Name of the table to be processed.
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Schema and Edit
Schema
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A schema is a row description. It defines the number of fields to be processed and passed on
to the next component. The schema is either Built-In or
stored remotely in the Repository.
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Built-In: You create and store the schema locally for this
component only. Related topic: see Talend Studio
User Guide.
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Repository: You have already created the schema and
stored it in the Repository. You can reuse it in various projects and Job designs. Related
topic: see Talend Studio User Guide.
When the schema to be reused has default values that are integers or functions, ensure that
these default values are not enclosed within quotation marks. If they are, you must remove
the quotation marks manually.
For more details, see https://help.talend.com/display/KB/Verifying+default+values+in+a+retrieved+schema.
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Click Edit schema to make changes to the schema. If the
current schema is of the Repository type, three options are
available:
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View schema: choose this option to view the
schema only.
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Change to built-in property: choose this option
to change the schema to Built-in for local
changes.
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Update repository connection: choose this option to change
the schema stored in the repository and decide whether to propagate the changes to
all the Jobs upon completion. If you just want to propagate the changes to the
current Job, you can select No upon completion and
choose this schema metadata again in the [Repository
Content] window.
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Query type
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Either Built-in or
Repository.
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Built-in: Fill in manually the
query statement or build it graphically using SQLBuilder
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Repository: Select the relevant query stored in the
Repository. The Query field gets
accordingly filled in.
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Guess
Query
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Click the Guess Query button to
generate the query which corresponds to your table schema in the
Query field.
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Query
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Enter your DB query paying particularly attention to properly
sequence the fields in order to match the schema definition.
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Die on error
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This check box is clear by default. This allows you to skip the
row on error and complete the process for error-free rows. If
needed, you can retrieve the rows on error via a Row > Rejects link.
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Advanced settings
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Additional JDBC parameters
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Specify additional connection properties for the database
connection you are creating. This option is not available if you
have selected the Use an existing
connection check box in the Basic settings.
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Propagate QUERY’s record set
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Select this check box to insert the result of the query in a
COLUMN of the current flow. Select this column from the use column list.
Note
This option allows the component to have a different schema
from that of the preceding component. Moreover, the column that
holds the QUERY’s record set should be set to the type of
Object and this component
is usually followed by tParseRecordSet.
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Use PreparedStatement
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Select this check box if you want to query the database using a
PreparedStatement. In the Set
PreparedStatement Parameter table, define the
parameters represented by “?” in the SQL instruction of the
Query field in the Basic Settings tab.
Parameter Index: Enter the
parameter position in the SQL instruction.
Parameter Type: Enter the parameter
type.
Parameter Value: Enter the
parameter value.
Note
This option is very useful if you need to execute the same
query several times. Performance levels are increased
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tStatCatcher Statistics
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Select this check box to collect log data at the component
level.
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Dynamic settings
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Click the [+] button to add a row in the table and fill
the Code field with a context variable to choose your
database connection dynamically from multiple connections planned in your Job. This feature
is useful when you need to access database tables having the same data structure but in
different databases, especially when you are working in an environment where you cannot
change your Job settings, for example, when your Job has to be deployed and executed
independent of Talend Studio.
The Dynamic settings table is available only when the
Use an existing connection check box is selected in the
Basic settings view. Once a dynamic parameter is
defined, the Component List box in the Basic settings view becomes unusable.
For more information on Dynamic settings and context
variables, see Talend Studio User Guide.
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Global Variables
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QUERY: the SQL query statement being processed. This is a
Flow variable and it returns a string.
ERROR_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error check box is
cleared, if the component has this check box.
A Flow variable functions during the execution of a component while an After variable
functions after the execution of the component.
To fill up a field or expression with a variable, press Ctrl +
Space to access the variable list and choose the variable to use from it.
For further information about variables, see Talend Studio
User Guide.
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Usage
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This component offers the flexibility of the database query and
covers all possible SQL queries.
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Log4j
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The activity of this component can be logged using the log4j feature. For more information on this feature, see Talend Studio User
Guide.
For more information on the log4j logging levels, see the Apache documentation at http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Level.html.
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Limitation
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Due to license incompatibility, one or more JARs required to use this component are not
provided. You can install the missing JARs for this particular component by clicking the
Install button on the Component tab view. You can also find out and add all missing JARs easily on
the Modules tab in the Integration perspective
of your studio. For details, see https://help.talend.com/display/KB/How+to+install+external+modules+in+the+Talend+products
or the section describing how to configure the Studio in the Talend Installation and Upgrade
Guide.
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