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excludeOlder Versions|Additional Resources|Related Links|Related Information

Snap type:

Read


Description:

This Snap outputs a list of tables in a database. The Snap will connect to the database, read its metadata, and output a document for each table found in the database. The table names are output in a topological order so that tables with the fewest dependencies are output first. In other words, if table A has a foreign key reference to table B, then table B will be output before A. The ordering is intended to ease the process of replicating a group of tables from one database to another.


  • Expected input: [None]
  • Expected output: Documents with the following fields:

    • name -  The fully-qualified name of the table. To use the table name in another Snap, like a Select or Insert, you can pass it through a ForEach Snap to another pipeline with the Select or Insert.

    • type - The type of table. This value is currently fixed to the string "TABLE".

    • dependents - (If Compute table graph is selected) A list of table names that have references to this table, including this table.

Replicating a Subset of Tables

The output of the Table List Snap can be directly used to replicate an entire database. However, if you are only interested in a subset of tables, you can use a Filter Snap to select the table names you are interested in as well as the tables that they reference. For example, given the following diamond-shaped table graph where A depends on B and C and they both depend on D:

Code Block
       A
      / \
     B   C
      \ /
       D

The TableList will output the following documents: 

Code Block
name=D; dependents=[A, B, C, D]
name=C; dependents=[A, C]
name=B; dependents=[A, B]
name=A; dependents=[A]

So, if you wanted to copy just table 'A' and its dependencies, you can add a Filter Snap with the following expression: 

Code Block
 $.dependents.indexOf('A') != -1

The filter will then remove any extra tables that happen to be in the schema.


Prerequisites:

[None]


Support and limitations:
Account: 

This Snap uses account references created on the Accounts page of SnapLogic Manager to handle access to this endpoint. See MySQL Account for information on setting up this type of account.


Views:


InputThis Snap has at most one document input view.
OutputThis Snap has at most one document output view.
ErrorThis Snap has at most one document error view and produces zero or more documents in the view.


Settings

Label



Required. The name for the Snap. You can modify this to be more specific, especially if you have more than one of the same Snap in your pipeline.

Schema name



The database schema name. Selecting a schema filters the Table name list to show only those tables within the selected schema. The property is suggestible and will retrieve available database schemas during suggest values.

Example: test

Default value: [None]


Compute table graph

Computes the dependents among tables and returns each table with a list of tables it has foreign key references to. The ordering of outputted tables is from least dependent to most-dependent. Note that as turning on this option will significantly slow down the Snap, it should be left as off unless you need it.
Default value: Not selected



 Example

In this pipeline, the MySQL Table List Snap, lists all the tables from a schema, formats to the JSON, writes to an output view and sends the result to an email address via the Email Sender Snap.


The MySQL Table List lists all the tables under the schema psadb.

The  output preview from the MySQL Table List Snap is as displayed below:



The output view from MySQL Table List is formatted to JSON and written to a file using the JSON Formatter and File Reader Snap respectively. The result is sent to an email address as an attachment using the Email Sender Snap. The settings of the Email Sender Snap and the email are as displayed below:


Insert excerpt
MySQL Snap Pack
MySQL Snap Pack
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