RDB$SUBSCRIPTIONS
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Subscription information is stored in a new system relation RDB$SUBSCRIPTIONS with a unique key on RDB$SUBSCRIPTION_NAME, RDB$SUBSCRIBER_NAME, RDB$DESTINATION. Additional fields store control information to facilitate "check in" and "check out" of changed data.
This includes transaction IDs, timestamps and transactional context of last observation of changed data on the schema object. The term "check out" denotes SELECT of changed columns of rows from subscribed tables when a subscritpion has been activated. The term "check in" refers to INSERT, UPDATE and DELETE of changed columns of rows from subscribed tables when a subscription has been activated. A subscription becomes activated during a database session with the execution of OPEN SUBSCRIPTION. It is deactivated with the execution of CLOSED SUBSCRIPTION.
RDB$SUBSCRIPTION
| Column name | Data type | Length | Description |
|---|---|---|---|
|
|
|
67 |
Name of subscription |
|
|
|
67 |
Name of relation or view |
|
|
|
67 |
Name of field |
|
|
|
Subtype text: User-written description of subscription | |
|
RDB$SECURITY CLASS |
CHAR |
67 |
Security class of the subscription (the owner for SQL security purposes) |
|
RDB$OWNER_NAME |
CHAR |
67 |
User who created the subscription |
|
RDB$RUNTIME |
BLOB |
Runtime binary information to enhance performance | |
|
RDB$FLAGS |
SMALLINT |
2 |
|
|
RDB$INSERT |
BOOLEAN |
2 |
Inserts are tracked |
|
RDB$UPDATE |
BOOLEAN |
2 |
Updates are tracked |
|
RDB$DELETE |
BOOLEAN |
2 |
Deletes are tracked |
|
RDB$CHANGE |
BOOLEAN |
2 |
Tracks all operations, but returns as soon as any column changes |