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TIMESTAMP: This is a DATE and a TIME put together in one variable (e.g. 2011-05-03 15:51:36.123456). TIMESTAMP WITH TIME ZONE: the same as TIMESTAMP, but including details about the time zone in question. The SQL function EXTRACT can be used for extracting
but the transaction started before the object's write timestamp it means that something changed the object's data after the transaction started. In this case, the transaction is canceled and must be restarted. and the transaction started after the object's write timestamp, it means that it is safe to read the object. In this case, if the ...
Enforcing the Thomas write rule only requires checking to see if the write timestamp of the object is greater than the time stamp of the transaction performing a write. If so, the write is discarded In the example above, if we call TS(T) the timestamp of transaction T, and WTS(O) the write timestamp of object O, then T2's write sets WTS(C) to ...
CREATE OR REPLACE TRIGGER TableTrigger AFTER INSERT OR UPDATE OR DELETE ON OriginalTable FOR EACH ROW DECLARE Now TIMESTAMP; BEGIN SELECT CURRENT_TIMESTAMP INTO Now FROM Dual; UPDATE HistoryTable SET EndDate = Now WHERE EndDate IS NULL AND Column1 =: OLD. Column1; IF: NEW. Column1 IS NOT NULL THEN INSERT INTO HistoryTable (Column1, Column2 ...
In analogy with relational databases, a column family is as a "table", each key-value pair being a "row". Each column is a tuple consisting of a column name, a value, and a timestamp. In a relational database table, this data would be grouped together within a table with other non-related data. Two types of column families exist:
The term "timestamp" derives from rubber stamps used in offices to stamp the current date, and sometimes time, in ink on paper documents, to record when the document was received. Common examples of this type of timestamp are a postmark on a letter or the "in" and "out" times on a time card .
(This is because a later transaction already depends on the old value.) Otherwise, T i creates a new version of object P and sets the read/write timestamp TS of the new version to the timestamp of the transaction TS ← TS(T i). [2] The drawback to this system is the cost of storing multiple versions of objects in the database.
SQL:2011 or ISO/IEC 9075:2011 (under the general title "Information technology – Database languages – SQL") is the seventh revision of the ISO (1987) and ANSI (1986) standard for the SQL database query language. It was formally adopted in December 2011. [1] The standard consists of 9 parts which are described in detail in SQL.