Table structure

  • Updated on Apr 13, 2022
  • Published on Dec 23, 2021
  • 2 minute(s) read
  • JW
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The table in your Tenant is constructed using a single-table design pattern, where the items or rows in the table may be super-wide but very sparse.

Specifically, the table defines the following fields. Additional fields that you store per item are entirely up to you.

Fields

Field Type Description Required
pk String The partition or hash key for the table Y
sk String The sort or range key for the table Y
lsi0_sk String The sort or range key for the index lsi0 N
lsi1_sk String The sort or range key for the index lsi1 N
lsi2_sk String The sort or range key for the index lsi2 N
lsi3_sk String The sort or range key for the index lsi3 N
lsi4_sk String The sort or range key for the index lsi4 N
ttl Number The Time-To-Live for the item, in Unix epoch time formate N
  • It is strongly recommended that you do not assign any meaning to the pk or various sk fields, and that each of these fields is effectively a copy of a meaningful field that you add to the item.
  • While the ttl is optional, EchoStream strongly recommends that you use it. It allows your table to automatically clean up old items. You will pay for all items in the table, even those you have lost reference to, and automatic cleanup mitigates this.

Indexes

Index Keys Use
table pk plus sk The primary table index. Supports discrete GetItem calls as well as Query calls
lsi0 pk plus lsi0_sk A Local Secondary Index. Supports Query calls using the secondary sort key
lsi1 pk plus lsi1_sk A Local Secondary Index. Supports Query calls using the secondary sort key
lsi2 pk plus lsi2_sk A Local Secondary Index. Supports Query calls using the secondary sort key
lsi3 pk plus lsi3_sk A Local Secondary Index. Supports Query calls using the secondary sort key
lsi4 pk plus lsi4_sk A Local Secondary Index. Supports Query calls using the secondary sort key
  • The pk and sk, in combination, must be unique. If your pk is unique and you do not need the sk, put in a placeholder value for the sk.
  • Items in your table may provide any number of the lsiX_sk fields for the corresponding indexes, including providing none of them (and just using the table index).
  • You may have as many items that declare duplicate lsiX_sk fields as you wish. If you do this, your Query calls on the lsiX indexes will return multiple items.
  • It is strongly recommended that you use the indexes provided where possible. While Scan calls are allowed, they are expensive and slow.