YouTube IDs¶
Every YouTube video ID that the library holds, once.
This page is the dictionary for the table. It holds the definition and purpose of every field, and it is where a field is changed.
Fields¶
| Field | Key | Type | Required | Allowed values or link | Definition | Purpose | Notes |
|---|---|---|---|---|---|---|---|
YouTube_Video_ID |
YOUTUBE_IDS.YOUTUBE_VIDEO_ID |
Text | Yes | The 11-character YouTube video ID. | Keeps a video and an MTV piece from ever holding the same ID. | ||
Item_Kind |
YOUTUBE_IDS.ITEM_KIND |
One value from a list | Yes | Video, MTV | Whether the ID belongs to a video of a song or to an MTV piece. | Says which table holds the row for the ID. |
Constraints¶
What the database enforces on each field, beyond its type. A field that is not listed has no default, no uniqueness, no range and no reference. Every field marked Required is NOT NULL.
| Field | Default | Unique | Range or pattern | Refers to |
|---|---|---|---|---|
YouTube_Video_ID |
Yes | exactly 11 letters, digits, - or _ (V-05) | ||
Item_Kind |
ref_YouTube_Item_Kinds |
Rules across fields:
core_Videosandcore_MTVeach have a generated constant column,YouTube_Item_Kind(Video in one, MTV in the other), and a composite foreign key fromYouTube_Video_IDandYouTube_Item_Kindto this table. An ID of one kind therefore cannot be held by the other, and an ID can be held only once.
The table is core_YouTube_IDs. Every link refuses a missing target and refuses the deletion of a row that another row still points to.
Choice values¶
Item_Kind¶
| Value | Meaning | Purpose |
|---|---|---|
| Video | The ID belongs to a row of core_Videos. | |
| MTV | The ID belongs to a row of core_MTV. |