The Vertica - Table List Snap outputs a list of tables in a database.

The Snap connects to the database, reads its metadata, and outputs 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: N/A

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".

• This is a Write-type Snap.
• Works in Ultra Tasks

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:

       A
      / \
     B   C
      \ /
       D

The Table List will output the following documents:

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:

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

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

Prerequisites

None.

Supported Accounts

Snap views

Snap settings