Teradata Execute

Overview

The Teradata Execute Snap allows you to execute a Teradata statement.

It works only with single queries and supports simple DML (SELECT, INSERT, UPDATE, DELETE) type statements. If a select query is executed, the query's results are merged into the incoming document, and any existing keys will have their values overwritten. On the other hand, the original document is written if there are no results from the query.

CAUTION: You can drop your database with it, so be cautious.


Prerequisites

  • A valid account with the required permissions.

Known issues

Creating stored procedures is not supported with Execute Snap. However, you can only invoke the existing stored procedures.

Behavior changes

In 4.26, when the stored procedures were called using the Database Execute Snaps, the queries were treated as write queries instead of read queries. So the output displayed message and status keys after executing the stored procedure. In 4.27, all the Database Execute Snaps run stored procedures correctly, that is, the queries are treated as read queries. The output now displays message key, and OUT params of the procedure (if any). The status key is not displayed.

If the stored procedure has no OUT parameters then only the message key is displayed with value success. If you have any existing Pipelines that are mapped with status key or previous description then those Pipelines will fail. So, you might need to revisit your Pipeline design.

Snap views

Type Description Examples of upstream and downstream Snaps
Input

This Snap has at most one document input view.

If the input view is defined, then the where clause can substitute incoming values for a given expression.

Output

This Snap has at most one document output view.

If an output view is available and an update/insert/merge/delete statement was executed, then the original document that was used to create the statement will be output with the status of the statement executed.

Valid JSON paths that are defined in the where clause for queries/statements will be substituted with values from an incoming document.

Learn more about Error handling.

Snap settings

Legend:
  • Expression icon (): Allows using pipeline parameters to set field values dynamically (if enabled). SnapLogic Expressions are not supported. If disabled, you can provide a static value.
  • SnapGPT (): Generates SnapLogic Expressions based on natural language using SnapGPT. Learn more.
  • Suggestion icon (): Populates a list of values dynamically based on your Snap configuration. You can select only one attribute at a time using the icon. Type into the field if it supports a comma-separated list of values.
  • Upload : Uploads files. Learn more.
Learn more about the icons in the Snap settings dialog.
Field/Field set Description
Label

String

Required. Specify a unique name for the Snap. Modify this to be more appropriate, especially if more than one of the same Snaps is in the pipeline.

Default value: Teradata Execute

SQL statement*

String/Expression

Required. Specify the SQL statement to execute on the server.

There are two possible scenarios that you encounter when working with SQL statements in SnapLogic. You must understand the following scenarios to successfully execute your SQL statements:

Scenario 1: Executing SQL statements without expressions

If the expression toggle of the SQL statement field is disabled:

  • The SQL statement must not be within quotes.
  • The $<variable_name> parts of the SQL statement are expressions. In the below example, $id and $book.

Additionally, the JSON path is allowed only in the WHERE clause. If the SQL statement starts with SELECT (case-insensitive), the Snap regards it as a select-type query and executes once per input document. If not, it regards it as write-type query and executes in batch mode.

Scenario 2: Executing SQL queries with expressions

If the expression toggle of the SQL statement field is selected:

  • The SQL statement must be within quotes.
  • The + $<variable_name> + parts of the SQL statement are expressions, and must not be within quotes. In the below example, $tablename.
  • The $<variable_name> parts of the SQL statement are bind parameter, and must be within quotes. In the below example, $id and $book.
Note: Table name and column names must not be provided as bind parameters. Only values can be provided as bind parameters.
  • We recommend that you add a single query in the SQL Statement field.
  • When the SQL statement property is an expression, the Pipeline parameters are shown in the suggest, but not the input schema.
Note:
  • The non-expression form uses bind parameters, making it significantly faster than executing N arbitrary SQL expressions. With the SQL statement property set as an expression, the Snap is vulnerable to SQL injection. Please use this feature with caution.
  • The '$' sign and identifier characters, such as double quotes ("), single quotes ('), or back quotes (`), are reserved characters and should not be used in comments or for purposes other than their originally intended purpose.
Warning:

Single quotes in values must be escaped

Any relational database (RDBMS) treats single quotes (') as special symbols. So, single quotes in the data or values passed through a DML query may cause the Snap to fail when the query is executed. Ensure that you pass two consecutive single quotes in place of one within these values to escape the single quote through these queries.

Single quote escaping examples:

  • String has no single quotes: To pass Schaum Series, use 'Schaum Series'
  • String contains single quotes: To pass O'Reilly's Publication, use 'O''Reilly''s Publication'

Default value: N/A

Query type

Dropdown list

Select the type of query for your SQL statement (Read or Write).

The default option, Auto, attempts to infer the type based on your SQL statement. Read is used with SELECT statements, Write is used with INSERT, UPDATE, or DELETE.

Default value: Auto

Query band

String/Expression

Specify the name-value pairs to use in the session's generated query band statement. The query band is passed to the Teradata database as a list of name-value pairs separated by semi-colons.

Default value: N/A

Example: ProjectName=dstage1;user=test;

Pass through

Checkbox

Select this checkbox to pass the input document to the output view under the key 'original'. This property applies only to the Execute Snaps with SELECT statement.

Default value: Selected

Ignore empty result

Checkbox

Select this checkbox to ignore empty result; no document will be written to the output view when a SELECT operation does not produce any result. If you deselect this checkbox and select the Pass through checkbox, the input document will be passed to the output view.

Default value: Deselected

Number of retries

Integer

The number of retry attempts the Snap makes in case of a connection failure.

Default value: 3

Retry interval (seconds)

Integer

The interval in seconds between retry attempts.

Default value: 1

Auto commit

Dropdown list

Select one of the options for this property to override the state of the Auto commit property on the account. The Auto commit at the Snap-level has three values: True, False, and Use account setting. The expected functionality for these modes are:

  • True - The Snap will execute with auto-commit enabled regardless of the value set for Auto commit in the Account used by the Snap.
  • False - The Snap will execute with auto-commit disabled regardless of the value set for Auto commit in the Account used by the Snap.
  • Use account setting - The Snap will execute with Auto commit property value inherited by the Account used by the Snap.
Note: 'Auto commit' may be enabled for certain use cases if PostgreSQL jdbc driver is used in either Redshift, PostgreSQL or generic JDBC Snap. But the JDBC driver may cause out of memory issues when Select statements are executed. In those cases, "Auto commit" in Snap property should be set to 'False' and the Fetch size in the "Account setting" can be increased for optimal performance.

Behavior of DML Queries in Database Execute Snap when auto-commit is false

DDL queries used in the Database Execute Snap will be committed by the Database itself, regardless of the Auto-commit setting. When Auto commit is set to false for the DML queries, the commit is called at the end of the Snap's execution. The Auto commit needs to be true in a scenario where the downstream Snap does depend on the data processed on an Upstream Database Execute Snap containing a DML query. When the Auto commit is set to the Use account setting on the Snap, the account level commit needs to be enabled.

Default value: Use account setting

Example: False

Advanced options

Dropdown list

Select the option 'Timestamp with microsecond precision' to support the microsecond precision for TIMESTAMP data type. The SELECT query for TIMESTAMP columns produces string values with microsecond precision in the output documents.

Default value: None

Snap execution

Dropdown list
Choose one of the three modes in which the Snap executes. Available options are:
  • Validate & Execute. Performs limited execution of the Snap and generates a data preview during pipeline validation. Subsequently, performs full execution of the Snap (unlimited records) during pipeline runtime.
  • Execute only. Performs full execution of the Snap during pipeline execution without generating preview data.
  • Disabled. Disables the Snap and all Snaps that are downstream from it.

Troubleshooting

Error Cause Resolution
Failure: Failed to execute query error code: 5992 A syntax error was found in the QUERY_BAND. Verify that the query band is in the format specified in the Query band field above. For example, if priority=1;workload=high in the Query band, add a semi-colon and update the value to priority=1;workload=high;.