Microsoft SSIS - Simple staging example¶

Model¶

For this stage package the Source model is used.

Template¶

stg_load_system_name_entity_name.dtsx¶

A SSIS package is created with the following components (note the @XGenSection annotations in the description fields of various components):

Control Flow¶

We have a staging package which needs to be created for every entity in our model. Because of this we want the create a section using the Control Flow of the SSIS package. So we click on the grey area of the package and add the annotation @XGenSection(name="stgPackage") in the Description property.

On the Control Flow we have a Data Flow Task with the name 'Load entity_name'. In the configuration for CrossGenerate we will bind the entity elements on the stgPackage section so the entity_name is resolved correctly.

Data Flow¶

In the DataFlow task of this template we have: - A OLE DB Source component to retrieve the data from the source table - A Derive Column component to add the StageDateTime as a column to the output - A OLE DB Destination component to write the data to the Destination table.

Here the system_name and entity_name placeholders will be resolved automatically, since these component are withing the stgPackage section.

Template Data Flow

Source¶

In the OLE DB Source component we go through the different screens and set the CrossGenerate annotations accordingly.

Connection Manager¶

In the connection manager screen we don't need to set anything specific for CrossGenerate, we make sure the connection is set correctly and the right source table is selected.

Template Source Connection Manager

Columns¶

In the 'Columns' tab here we also don't need to set anything specific for CrossGenerate. The attribute which needs to be repeated for every attribute in the model needs to be there and selected. We can't specify a section here in this screen, but we will do this using the Advanced Editor of the source component.

Template Source Columns

Input and Output Properties - External Columns¶

When opening the Advanced Editor for the source component we can go to the 'Input and Output Properties' tab to find the 'attribute_name' column in the 'External Columns' list. The defined output column needs to be repeated for every attribute in our model, so we set the section named 'Attribute' on the [External Columns/attribute_name] element. This way CrossGenerate knows which part in the template to repeat (in this case the [attribute_name] column).

Template Source Input and Output Properties - External Columns

Input and Output Properties - Output Columns¶

We do the same for the 'Output Columns', since this column also needs to be repeat for every attribute defined in the model.

Template Source Input and Output Properties - Output Columns

Input and Output Properties - Error Output Columns¶

And again the same of the 'OLDE DB Source Error Output' output columns.

Template Source Input and Output Properties - Error Output Columns

Destination¶

Connection Manager¶

Also for the Destination connection manager, nothing particular needs to be specified for CrossGenerate.

Template Destination Connection Manager

Mappings¶

In the mappings tab we make sure all columns are mapped. Here the mapping of the attribute_name column should be repeated for every attribute specified in the model. As with the source component we cannot specify an annotation in this screen, for this we need to open the 'Advanced Editor'.

Template Destination Mappings

Input and Output Properties - External Columns¶

Template Destination Input and Output Properties - External Columns

Input and Output Properties - Input Columns¶

Template Destination Input and Output Properties - Input Columns

Documentation¶

For documentation on templates, please see Template.

Config¶

Enrich the model with SSIS datatypes using Model Attribute Injection¶

The model used as input for this example contains columns that are specified with a database-datatype (varchar, int, datetime etc). SSIS uses it's own set of datatypes. For the model to be used to map to a SSIS template, first the model needs to be enriched with SSIS datatype characteristics. This model enrichment is done using a specific CrossGenerate feature named Model Attribute Injection. This feature enables adding attributes to elements in the model.

Model Attribute Injection is configured in the first part of the config shown below: Each database datatype used in the model is mapped to its corresponding SSIS datatype. This SSIS datatype is stored in the etldatatype XML attribute of the model's attribute. For attributes of varchar or nvarchar datatypes an additional attribute is injected with the codePage (with a value of 1252). The xml snippet below shows an example of Model Attribute Injection configuration.

<ModelAttributeInjection
  modelXPath="//attribute[@datatype='varchar']"
  targetAttribute="etldatatype"
  targetValue="str"
/>
<ModelAttributeInjection
  modelXPath="//attribute[@datatype='varchar']"
  targetAttribute="codePage"
  targetValue="1252"
/>

Prepare the SSIS template package using Template Attribute Injection and Template Placeholder Injection¶

Before code can be generated using the SSIS template package and the enriched model, some alterations need to be performed on the SSIS template package:

Parts in the SSIS template that are mapped to a model attribute (column) need to be extended with XML attributes that might be needed.
Some attributes in the SSIS templates that have concrete values need to be populated using a placeholder.

Add attributes using Template Attribute Injection¶

Similar to Model Attribute Injection, parts of a template can also be extended with properties. For this Template Attribute Injection can be configured in CrossGenerate.

In the example configuration below the attributes scale, precision, cachedScale and cachedPrecision are added to each node that has an attribute name with value attribute_name. These attributes are injected so that, when a attribute/column is applied on the template that has scale or precision specifications, these can be mapped to the template. An example of Template Attribute Injection:

<TemplateAttributeInjection
  parentNodeXPath="//*[@name='attribute_name']" 
  attributeName="scale" 
  defaultValue=""
/>

Add placeholders to a template using Template Placeholder Injection¶

When developing a template SSIS package, a lot of elements can be made abstract using Visual Studio Data Tools. This means that for table or column names, a SSIS package can be developed against an abstract datamodel. So the SSIS package is build using placeholder names, which automatically makes it a template (for example 'attribute_name').

Other elements, for example data types, length & precision cannot be made abstract; the IDE requires you to specify concrete, existing datatypes and lengths for columns. When applying a model to a template SSIS package, it is required that the data type, length and other characteristics are substituted from the model. This is only possible if the elements that need to be subsituted contain placeholders in the SSIS template package.

Template Placeholder Injections enables inserting placeholders in a template in parts that cannot be made abstract from the IDE. An example of a template placeholder injection is shown below:

<TemplatePlaceholderInjection 
  templateXPath="//*[@name='attribute_name']/@dataType"  
  modelNode="etldatatype" 
  scope="current"
/>

The example looks for all elements in the template that have a name attribute with value attribute_name. For these elements the dataType attribute is populated with a placeholder referencing the etldatatype attribute from the model.

Specifying additional sections¶

As can be seen in the config below, there is a section defined named Attribute that references input columns for an OLE DB Destination Input. This section is defined in the config since the input columns on the OLE DB Destination input cannot be given a section annotation in the IDE.

<Section
  name="Attribute" 
  templateXPath="//input[@name='OLE DB Destination Input']/inputColumns/inputColumn[@cachedName='attribute_name']"
/>

Full config example¶

<?xml version="1.0" encoding="UTF-8"?>
<XGenConfig>
  <Model>    
    <ModelAttributeInjections>
      <!-- Translate the SQL data type into the SSIS data type and store it in the 'etldatatype' attribute on the attribute elements in the model. -->
      <ModelAttributeInjection modelXPath="//attribute[@datatype='varchar']" targetAttribute="etldatatype" targetValue="str"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='varchar']" targetAttribute="codePage" targetValue="1252"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='nvarchar']" targetAttribute="etldatatype" targetValue="wstr"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='nvarchar']" targetAttribute="codePage" targetValue="1252"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='tinyint']" targetAttribute="etldatatype" targetValue="i2"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='smallint']" targetAttribute="etldatatype" targetValue="i2"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='bigint']" targetAttribute="etldatatype" targetValue="i8"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='int']" targetAttribute="etldatatype" targetValue="i4"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='timestamp']" targetAttribute="etldatatype" targetValue="bytes"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='datetime']" targetAttribute="etldatatype" targetValue="dbTimeStamp"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='datetime2']" targetAttribute="etldatatype" targetValue="dbTimeStamp"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='decimal']" targetAttribute="etldatatype" targetValue="numeric"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='bit']" targetAttribute="etldatatype" targetValue="bool"/>
      <ModelAttributeInjection modelXPath="//attribute[@datatype='uniqueidentifier']" targetAttribute="etldatatype" targetValue="guid"/>
    </ModelAttributeInjections>
  </Model>
  <Template rootSectionName="StgPackage">
    <!-- Define the FileFormat, here all attributes with the name 'description' are scanned for annotations. -->
    <FileFormat templateType="xml" currentAccessor="_" commentNodeXPath="@*[lower-case(local-name())='description']" annotationPrefix="@XGen" annotationArgsPrefix="(" annotationArgsSuffix=")" />
    <!-- Output a SSIS package per element of the root section, so 1 package per entity. -->
    <Output type="output_per_element" />
    <Sections>
      <!-- The input columns of the 'OLE DB Destination Input' need to be repeated for every attribute. -->
      <!-- This element doesn't have a 'Description' attribute, so we need to create this section in this config file. -->
      <Section name="Attribute" templateXPath="//input[@name='OLE DB Destination Input']/inputColumns/inputColumn[@cachedName='attribute_name']"/>
    </Sections>
    <TemplateAttributeInjections>
      <!-- Inject an attribute for the scale, precision, cachedScale & cachedPrecision on elements where the name is 'attribute_name'. -->
      <TemplateAttributeInjection parentNodeXPath="//*[@name='attribute_name']" attributeName="scale" defaultValue=""/>
      <TemplateAttributeInjection parentNodeXPath="//*[@name='attribute_name']" attributeName="precision" defaultValue=""/>
      <TemplateAttributeInjection parentNodeXPath="//*[@name='attribute_name']" attributeName="cachedScale" defaultValue=""/>
      <TemplateAttributeInjection parentNodeXPath="//*[@name='attribute_name']" attributeName="cachedPrecision" defaultValue=""/>
    </TemplateAttributeInjections>
    <TemplatePlaceholderInjections>
      <!-- Inject a placeholder for the dataType, length, precision, scale, codePage attributes for the columns. -->
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@dataType"  modelNode="etldatatype" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@length"  modelNode="length" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@precision"  modelNode="precision" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@scale"  modelNode="scale" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@codePage"  modelNode="codePage" scope="current" />
      <!-- Inject a placeholder for the cachedDataType, cachedLength, cachedPrecision, cachedScale, cachedCodePage attributes for the columns. -->
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@cachedDataType" modelNode="etldatatype" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@cachedLength"  modelNode="length" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@cachedPrecision"  modelNode="precision" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@cachedScale"  modelNode="scale" scope="current" />
      <TemplatePlaceholderInjection templateXPath="//*[@name='attribute_name']/@cachedCodePage"  modelNode="codePage" scope="current" />
    </TemplatePlaceholderInjections>
  </Template>
 <Binding>
   <!-- Create a binding between the 'StgPackage' sections in the template and the 'entity' elements in the model. -->
   <SectionModelBinding section="StgPackage" modelXPath="/modeldefinition/system/mappableObjects/entity" placeholderName="entity">
     <Placeholders>
       <!-- Create the 'system' placeholder within the 'StgPackage' section. -->
       <Placeholder name="system" modelXPath="../.." />                 
     </Placeholders>
     <!-- Create a binding between the 'Attribute' sections in the template and the 'attribute' elements in the model. -->
     <SectionModelBinding section="Attribute" modelXPath="attributes/attribute" placeholderName="attribute">
       <Placeholders>
         <!-- Create the 'system' placeholder within the 'Attribute' section. -->
         <Placeholder name="system" modelXPath="../../../.." />
         <!-- Create the 'entity' placeholder within the 'Attribute' section. -->
         <Placeholder name="entity" modelXPath="../.." />                 
       </Placeholders>    
     </SectionModelBinding>        
   </SectionModelBinding>
 </Binding>
</XGenConfig>

Documentation¶

For documentation on the configuration, please see Config.

Output¶

When running CrossGenerate the output using the given Model, Template and Config will be the following files:

stg_load_ExampleSource_Customer.dtsx
stg_load_ExampleSource_Order.dtsx

To test the packages, copy the template solution into a new folder. Open the solution and add the generated packages to the SSIS project. Updated the Source & Staging connection to the real Source & Staging databases which contain the Customer & Order tables.