Data-Integration-Developer Talend Data Integration Certified Developer Exam Questions and Answers

The tMysqlOutput component is used to write data into a MySQL database table. The Update and Delete operations are used to modify or remove existing rows in the table based on a primary key. To define the primary key for these operations, you need to use the Use field options check box in the Advanced settings view of the component. This will enable you to specify which columns are used as keys for each operation. You can also define other options for each column, such as nullable, length, precision, etc. The Use field options check box is not available in the Basic settings view of the component. The Additional columns options check box and the Use hint options check box are used for other purposes, such as adding extra columns or hints to the SQL query, and they do not affect the primary key definition. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tMysqlOutput properties - 7.3]

Tags are used to mark specific points in the development lifecycle of a project. This can be done for a variety of reasons, such as:

• To mark the completion of a major feature or release
• To mark the start of a new development phase (e.g., QA, production)
• To mark a known good state of the codebase (e.g., before a risky change)

Tags can be used to create branches, which can then be used to develop and test new features or bug fixes. They can also be used to deploy the codebase to different environments (e.g., development, staging, production).

Examples of when to use a tag:

• When you are ready to release a new version of your application to production.
• When you have completed a major feature or milestone in the development of your application.
• Before making a risky change to your codebase, such as a database migration or refactoring.
• When you need to deploy your application to a different environment, such as staging or production.

Benefits of using tags:

• Tags can help you to keep track of the different versions of your codebase.
• Tags can help you to roll back to a previous version of your codebase if necessary.
• Tags can help you to deploy your codebase to different environments.
• Tags can help you to collaborate with other developers more effectively.

References:

• Talend Best Practices Guide: https://help.talend.com/r/en-US/8.0/software-dev-lifecycle-best-practices-guide/branching-merging-and-tagging
• Git documentation on tags: https://git-scm.com/docs/git-tag

To retrieve records that have a specific value based on a variable, you can use a tDBInput component with a context variable in the SQL query. A context variable is a variable that can store a value that can be changed at runtime or between different contexts. A context variable can be used in various components to parameterize their properties or expressions. A tDBInput component is used to read data from a database table by executing an SQL query. You can use a context variable in the SQL query to filter the records based on a dynamic value. For example, if you have a context variable named country that stores the value of the country you want to filter by, you can use it in the SQL query of the tDBInput component as follows:

SELECT id, address, country FROM customers WHERE country = ‘context.country’

This will retrieve only the records that have the same value as the context variable country in the country column.

You do not need to use a Run if trigger, a tMatchGroup component, or a tFilterColumns component to achieve this. A Run if trigger is used to execute a subjob conditionally based on a logical expression. A tMatchGroup component is used to group similar records based on matching rules and output them as master or duplicate records. A tFilterColumns component is used to select or remove columns from an input flow based on a list of column names. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [Contexts - 7.3], [tDBInput properties - 7.3], [Run if properties - 7.3], [tMatchGroup properties - 7.3], [tFilterColumns properties - 7.3]

The code viewer tab in Talend Studio provides lines of code generated for the selected component in a Job. It shows the code in the language of the component, such as Java or Perl. The code viewer tab allows the user to view and edit the code, as well as copy and paste it to another editor. The code viewer tab also displays errors and warnings related to the code. References: Code viewer tab

A Joblet is a reusable piece of a job that can be used in multiple jobs as a single component. A tRunJob component is a component that allows you to call another job as a subjob within a parent job. When comparing a Joblet to a tRunJob component, these statements are true:

• A Joblet uses the same context variables of the job in which it is used, unlike a tRunJob component. A context variable is a variable that can store a value that can be changed at runtime or between different contexts. A Joblet inherits the context variables from the job that contains it and does not have its own context variables. A tRunJob component can pass context variables from the parent job to the child job, or use a specific context for the child job.
• Building a Joblet typically requires the use of generic input and trigger components. A Joblet can have one or more input and output flows that connect it with other components in a job. To create these flows, you need to use generic input and trigger components, such as tJobletInput, tJobletOutput, tJobletTriggerInput, and tJobletTriggerOutput. These components allow you to define schemas and triggers for your Joblet without depending on specific components.
• The nested job called by a tRunJob component cannot use the same context variables of the job in which it is used. A nested job is a job that is called by another job using a tRunJob component. A nested job can have its own context variables or receive context variables from its parent job, but it cannot use thesame context variables as its parent job. This means that if you have two context variables with the same name in both jobs, they will be treated as separate variables and will not share values.

These statements are false when comparing a Joblet to a tRunJob component:

• The performance of tRunJob component is better than running an equivalent job using a Joblet. The performance of a Joblet is better than running an equivalent job using a tRunJob component. This is because a Joblet is integrated into the main code of the job and does not require launching another JVM process or loading another metadata object like a tRunJob component does. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [Joblets - 7.3], [tRunJob properties - 7.3], [Contexts - 7.3]

To call a different job within a job you are developing, you can use the tRunJob component. This component allows you to execute another job as a subjob within a parent job. To pass the parameters to the job you want to call, you can use the context parameters. Context parameters are variables that can store values that can be changed at runtime or between different contexts. You can define context parameters in the Contexts tab of your job and assign them values for each context. You can also pass context parameters from the parent job to the child job by using the Context Param tab of the tRunJob component. This way, you can parameterize the properties or expressions of the child job with the values from the parent job.

You do not need to use a file, command line options, or Java function parameters to pass parameters to a different job. These methods are not supported by Talend Studio and may cause errors or unexpected results. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tRunJob properties - 7.3], [Contexts - 7.3]

The generic Input component used for in a Joblet design is the tJobletInput component. This component is used to carry data into a Joblet from another component in the job that contains the Joblet. A Joblet is a reusable piece of a job that can be used in multiple jobs as a single component. A Joblet can have one or more input and output flows that connect it with other components in a job. To create these flows, you need to use generic input and output components, such as tJobletInput, tJobletOutput, tJobletTriggerInput, and tJobletTriggerOutput. These components allow you to define schemas and triggers for your Joblet without depending on specific components.

The tJobletInput component is not used for triggering a Joblet, triggering a subjob, or carrying data into a subjob. These are different concepts and functionalities in Talend Studio. A trigger is a link that activates a subjob or a component based on a condition or an event. A subjob is a part of a job that consists of one or more components connected by data flows or triggers. A subjob can be triggered by another subjob using triggers such as OnSubjobOk, OnSubjobError, Run if, etc. A subjob can also carry data into another subjob using data flows such as main, lookup, reject, etc. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tJobletInput properties - 7.3], [Joblets - 7.3], [Triggers - 7.3]

To create an empty Joblet, you need to right-click on the Joblet Designs node in the Repository tree view and select Create Joblet option. This will open a dialog box whereyou can enter the name and description of your Joblet and select an icon for it. You can then design your Joblet by adding components and links to it in the Designer workspace.

You cannot create an empty Joblet by creating an empty job, then exporting it as a Joblet by right-clicking it in the Repository, creating an empty job and using the file menu to save it as Joblet, or right-clicking a space in the Designer and selecting refactor to Joblet. These methods are not available in Talend Studio and may cause errors or unexpected results. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [Joblets - 7.3]

The tMysqlOutput component is used to write data into a MySQL database table. The Action on table parameter of this component allows you to specify what operation to perform on the table before loading data into it. The Action on table parameter supports the following operations:

• Drop table if exists and create: This operation drops the table if it already exists in the database and creates a new one with the same name and structure as defined in the schema.
• Create table: This operation creates a new table in the database with the name and structure as defined in the schema. If a table with the same name already exists, an error will be raised.
• Create table if does not exist: This operation creates a new table in the database with the name and structure as defined in the schema only if there is no table with the same name already existing in the database. If a table with the same name already exists, no action will be taken.

The Action on table parameter does not support the following operations:

• Replace: This is not an operation on the table, but on the data. The Replace parameter of the tMysqlOutput component allows you to specify whether to replace existing rows in the table with new rows based on a key attribute or to insert new rows only.
• Drop table: This is not an operation on the table, but on the database. The Drop table parameter of the tMysqlConnection component allows you to specify whether to drop the table after closing the connection or not. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tMysqlOutput properties - 7.3], [tMysqlConnection properties - 7.3]

To call a different job within a job you are developing, you can use the tRunJob component. This component allows you to execute another job as a subjob within a parent job. To pass the parameters to the job you want to call, you can use the context parameters. Context parameters are variables that can store values that can be changed at runtime or between different contexts. You can define context parameters in the Contexts tab of your job and assign them values for each context. You can also pass context parameters from the parent job to the child job by using the Context Param tab of the tRunJob component. This way, you can parameterize the properties or expressions of the child job with the values from the parent job.

To transfer processed data stored in the tBufferOutput buffer memory back to the parent job, you need to select the Propagate the child result to output schema option in the Advanced settings of the tRunJob component. This option allows you to retrieve the data from the tBufferOutput component of the child job and send it to an output row of the parent job. The tBufferOutput component is used to store data in memory without writing it to disk or database. You can use this component to optimize the performance and memory usage of your job.

You do not need to select the Transmit whole context option in either Basic or Advanced settings of the tRunJob component. This option allows you to pass all the context parameters from the parent job to the child job without specifying them individually. This option does not affect the data transfer from the tBufferOutput component. You also do not need to select the Propagate the child result to output schema option in Basic settings of the tRunJob component, as this option is only available in Advanced settings. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tRunJob properties - 7.3], [tBufferOutput properties - 7.3], [Contexts - 7.3]

To create a job consisting of two subjobs, A and B, and add a Joblet C with the intention of running it between A and B, you need to do the following steps:

• Design subjob A by adding components and links to it in the Designer workspace.
• Add a Start component to mark the beginning of subjob B and link it to subjob A using an OnSubjobOk trigger.
• Design subjob B by adding components and links to it after the Start component in the Designer workspace.
• Add a tJobletTriggerInput component to your Joblet C design and link it to other components in your Joblet using data flows or triggers.
• Add a tJobletTriggerOutput component to your Joblet C design and link it to other components in your Joblet using data flows or triggers.
• Drag your Joblet C from the Repository tree view to the Designer workspace between subjob A and subjob B.
• Link your Joblet C to subjob A using an OnComponentOk trigger from the last component of subjob A to the tJobletTriggerInput component of your Joblet C.
• Link your Joblet C to subjob B using an OnComponentOk trigger from the tJobletTriggerOutput component of your Joblet C to the Start component of subjob B.

The minimum requirements to orchestrate this are adding TRIGGER_INPUT and TRIGGER_OUTPUT components into C and linking A, B, and C using OnSubjobOk triggers. These are generic components that allow you to define triggers for your Joblet without depending on specific components. You do not need to add TRIGGER_INPUT and TRIGGER_OUTPUT components into A or B, as these are regular subjobs that can use any type of components or triggers. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tJobletTriggerInput properties - 7.3], [tJobletTriggerOutput properties - 7.3], [Joblets - 7.3], [Triggers - 7.3]

To identify execution times to verify the effectiveness of your changes, you can use one of these methods:

• Reading the time stamps from the execution console in the Run view. This method allows you to see the start and end time of each subjob and component in your job, as well as the total execution time of the job. You can also see the number of rows processed by each component and the status of the job (success or failure).
• Observing the execution times that annotate the flows in the Designer. This method allows you to see the execution time of each flow (main, lookup, reject, etc.) between components in your job. You can also see the number of rows processed by each flow and the throughput (rows per second) of each flow.

You cannot use these methods to identify execution times:

• Observing the execution time in the Code view. This method does not show you the execution time of your job or its components, but only the generated code of your job in Java or Perl. The Code view is useful for debugging or customizing your code, but not for measuring performance.
• Comparing time stamps in Trace Debug mode. This method does not show you the execution time of your job or its components, but only the values of eachcolumn for each row processed by your job. The Trace Debug mode is useful for tracing data quality or transformation issues, but not for measuring performance. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [Run view - 7.3], [Designer - 7.3], [Code view - 7.3], [Trace Debug mode - 7.3]

The tLogCatcher component can catch exceptions from three types of components: tWarn, tDie, and Java Exception. The tWarn component is used to trigger a warning message that can be caught by the tLogCatcher component for an exhaustive log. The tDie component is used to stop the execution of a job or a subjob and return an error code that can be caught by the tLogCatcher component for an exhaustive log. The Java Exception component is used to handle any Java exception that occurs during the execution of a job or a subjob and pass it to the tLogCatcher component for an exhaustive log. The tLogCatcher component cannot catch exceptions from other types of components, such as OnSubjobError Exception or tAssertCatcher. The OnSubjobError Exception is a trigger that is activated when an error occurs in a subjob and can be used to perform some actions after the error, such as sending an email or logging a message. The tAssertCatcher component is a component that collects the assert data generated by the tAssert component and passes it on to the output defined. The tAssert component is used to verify if a condition is true or false and generate an assert data accordingly. References: Talend Open Studio: Open-source ETL and Free Data Integration | Talend, [tLogCatcher properties - 7.3], [tWarn properties - 7.3], [tDie properties - 7.3], [Java Exception properties - 7.3], [OnSubjobError properties - 7.3], [tAssertCatcher properties - 7.3], [tAssert properties - 7.3]