# tHSQLDbInput Executes a DB query with a strictly defined order which must correspond to the schema definition and then it passes on the field list to the next component via a Main row link. tHSQLDbInput reads a database and extracts fields based on a query. ## tHSQLDbInput Standard properties These properties are used to configure tHSQLDbInput running in the Standard Job framework. The Standard tHSQLDbInput component belongs to the Databases family. The component in this framework is available in all Talend products. ## Basic settings | Properties | Description | | --- | --- | | Property type |

Either Built-in or Repository .
Built-in: No property data stored centrally.
Repository: Select the repository file in which the properties are stored. The fields that follow are completed automatically using the data retrieved.

| | ![](https://help.qlik.com/talend/en-US/components/8.0/Resources/images/Save_Icon.png) | Click this icon to open a database connection wizard and store the
database connection parameters you set in the component Basic settings view.

For more information about setting up and storing database
connection parameters, see [Centralizing database metadata](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/centralizing-database-metadata). | | Running Mode | Select on the list the Server Mode corresponding to your DB setup
among the four propositions :

HSQLDb Server, HSQLDb WebServer, HSQLDb In Process Persistent, HSQLDb In Memory. | | Use TLS/SSL sockets | Select this check box to enable the secured mode if
required. | | Host | Database server IP address. | | Port | Listening port number of DB server. | | Database Alias | Alias name of the database. | | Username and
Password | DB user authentication data.

To enter the password, click the [...] button
next to the password field, enter the password in double quotes in the pop-up dialog box,
and click OK to save the settings. | | DB path | Specify the directory to the database you want to connect to. This
field is available only to the HSQLDb In
Process Persistent running mode.

Information noteNote:

By default, if the database you specify in this field does not
exist, it will be created automatically. If you want to change
this default setting, modify the connection parameter set in
the Additional JDBC parameter
field in the Advanced settings
view | | Db name | Enter the database name that you want to connect to. This field is
available only to the HSQLDb In Process
Persistent running mode and the HSQLDb In Memory running mode. | | Schema and Edit
schema |

A schema is a row description. It defines the number of fields (columns) to be processed and passed on to the next component. When you create a Spark Job, avoid the reserved word line when naming the fields.

This component offers the advantage of the dynamic schema feature. This allows you to retrieve unknown columns from source files or to copy batches of columns from a source without mapping each column individually. For further information about dynamic schemas, see Dynamic schema.

This dynamic schema feature is designed for the purpose of retrieving unknown columns of a table and is recommended to be used for this purpose only; it is not recommended for the use of creating tables.
Built-in: The schema is created and stored locally for this component only. For more information about a component schema in its Basic settings tab, see Basic settings tab.
Repository: The schema already exists and is stored in the Repository, hence can be reused. For more information about a component schema in its Basic settings tab, see Basic settings tab.
Click Edit schema to make changes to the schema. If the current schema is of the Repository type, three options are available:
- View schema: choose this option to view the schema only.
- Change to built-in property: choose this option to change the schema to Built-in for local changes.
- 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.

| | Query type and
Query | Enter your DB query paying particularly attention to properly
sequence the fields in order to match the schema definition.

*If using the dynamic schema
feature, the SELECT query must include the \* wildcard, to retrieve all of the columns from the table
selected.* | ## Advanced settings | Properties | Description | | --- | --- | | Additional JDBC parameters | Specify additional connection properties for the DB connection you
are creating. When the running mode is HSQLDb
In Process Persistent , you can set the connection
property ifexists=true to allow connection to an
existing database only and avoid creating a new database. | | Trim all the String/Char columns | Select this check box to remove leading and trailing whitespace
from all the String/Char columns. | | Trim column | Remove leading and trailing whitespace from defined
columns. | | tStat
Catcher Statistics | Select this check box to collect log data at the component
level. | ## Global Variables | Variables | Description | | --- | --- | | Global Variables | NB\_LINE: Indicates the number of
lines processed. This is an After variable and it returns an
integer.

QUERY: Indicates the query to be
processed. This is a Flow variable and it returns a string.

For further information about variables, see [Using contexts and variables](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/contexts-and-variables).

Information noteNote:

A Flow variable means it functions during the execution of a
component while an After variable means it functions after the
execution of a component. | ## Usage | Usage guidance | Description | | --- | --- | | **Usage rule** | This component covers all possible SQL queries for HSQLDb
databases. | | Connections | Outgoing links (from this component to another):

Row: Main; Iterate

Trigger: Run if; On Component Ok;
On Component Error; On Subjob Ok; On Subjob Error.

Incoming links (from one component to this one):

Row: Iterate;

Trigger: Run if; On Component Ok;
On Component Error; On Subjob Ok; On Subjob Error.

For further information regarding connections, see [Using connections in a Job](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/using-connections-in-job). | | Limitation | 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 Talend Studio. For
details, see [Installing external modules](https://help.qlik.com/talend/r/en-US/8.0/studio-user-guide/installing-external-modules). |