I am using MS SQL Server 2008 and I have an sql table with some data that is inserted daily at 6 am by an sql job. The problem I have is that some data has been inserted separately into the job and I need to know when this data was added.
Is there a query I can run that will show me this?
I think the short answer is NO, there's no magic, ad hoc SQL query that will let you go back after the fact and find out when a row was inserted.
If you want to know when a row is inserted, the easiest thing would be to simply add a date or timestamp field with a default value (like getDate()) that automatically fills in the date/time when the row is inserted.
There are, of course, SQL logs available that will let you track when rows are inserted, updated, deleted, etc., but those require set up and maintenance.
Third option would be to have the program that's inserting the data perform some logging.
Add a date field to the table. You can give it a default value of GETDATE()
Then ORDER BY that field.
SELECT Column1, Column2, NewDateColumn
FROM YourTable
ORDER BY NewDateColumn
what i would do is :
/* add new column to keep inserted row date */
ALTER TABLE [schemaName].[tableName] ADD [RecTime] DATETIME;
/* update the existing rows with the current date since there is no way to guess their insertion date */
UPDATE [schemaName].[tableName] SET [RecTime] = GETDATE();
/* and set a constraint to the RecTime column to set current date on every new row added */
ALTER TABLE [schemaName].[tableName] ADD CONSTRAINT [DF_tableName_RecTime] DEFAULT (GETDATE()) FOR [RecTime]
then you can get those rows like :
SELECT *
FROM [schemaName].[tableName]
WHERE NOT(DATEPART(hh, RecTime) = 6 AND DATEPART(mi, RecTime) <= 20)
you can 'play' with '20' if you know how long sql job run
you probably need to look at SQL CREATE TRIGGER to add the logic to know when the data is being added and log that info in another table for further actions. Without further details I am not sure we can say more than that.
As you're referring to data which has already been inserted, the answer is No, unless you already have a datetime column which has a default value of GETDATE(). The best you can manage after the event has occurred is to look at the sequence of rows and determine that it was between two known times.
Related
I have a SQL Server table with just 3 columns, one of which is of type varbinary. The data in this column is actually a Json document which among other properties contains information about when the data was last modified. Unfortunately the SQL table itself does not contain information about when its rows were modified.
Now when doing sorting and filtering of the data I of course don't want fetch all rows in order to find e.g. the latest 100 entries.
So my question is: does SQL Server somehow remember when a row was added/modified? I have tried adding a timestamp and this is applied to all existing rows but this is applied randomly I think, because the sorting doesn't work. I don't need a datetime or anything, I just want to be able sort the records based on when they were last modified.
Thanks
For those looking to insert a tamestamp column of type DateTime into an existing DB table, you can do this like so:
ALTER TABLE TestTable
ADD DateInserted DATETIME NOT NULL DEFAULT (GETDATE());
The existing records will automatically get the value equal to the date/time of the moment when column is added.
New records will get up-to-date value upon insertion.
SQL Server will not track historically when a row was inserted or modified so you need to rely on the JSON data to figure that out yourself. You are going to need a new column to make this efficient to query. Once you have your new column you have some options:
Loop through all your records populating the new column with the relevant value from the JSON data.
If your version of SQL Server is recent enough, you can query the JSON data directly. Populate this column using a query like this:
UPDATE MyTable
SET MyNewColumn = JSON_VALUE(JsonDataColumn, '$.Customer.DateCreated')
The downside of this method is that you need to maintain this
Make SQL Server compute the value from the JSON automatically, for example:
ALTER TABLE MyTable
ADD MyNewColumn AS JSON_VALUE(JsonDataColumn, '$.Customer.DateCreated')
And, create an index to make it efficient:
CREATE INDEX IX_MyTable_MyNewColumn
ON MyTable(MyNewColumn)
Use a new column CreatedDate and store datetime every time you make an Insert.
You could use GetDate() for inserting date in the column.
A UpdatedDate column can be used for updates.
in order to find e.g. the latest 100 entries.
Timestamp is indeed what you need.
It's ever-increasing value, it's updated automatically, so you are always able to find all last modified/inserted rows.
Here is an example:
create table dbo.test1 (id int);
insert into dbo.test1 values(1), (2), (3);
alter table dbo.test1 add ts timestamp;
update dbo.test1
set id = 10
where id = 2
select top 1 *
from dbo.test1
order by ts desc;
--id ts
--10 0x000000001FCFABD2
insert into dbo.test1 (id)
values (100);
select top 1 *
from dbo.test1
order by ts desc;
--id ts
--100 0x000000001FCFABD3
As you see, you always get the last modified/inserted row.
For your purpose just use
select top 100 *
...
order by ts desc;
Thanks. Apparently I didn't look hard enough before I posted this question. The question has been asked a couple of times before and the answer is: Nope! There is no easy solution to this.
SQL Server does not keep track of when a record was created or modified, which was somehow what I was looking for. So I will go for the next best solution, which is probably to create a datetime column, retrieve the modified date from the Json document and then update the record. Or rather, the 1,4 million records:-(
I want to delete new record if the same record created before.
My columns are date, time and MsgLog. If date and time are same, I want to delete new one.
I need help .
You can check in the table whether that value exists or not in the column using a query. If it exists, you can show message that a record already exists.
To prevent such kind of erroneous additions you can add restriction to your table to ensure unique #Date #Time pairs; if you don't want to change data structure (e.g. you want to add records with such restrictions once or twice) you can exploit insert select counstruction.
-- MS SQL version, check your DBMS
insert into MyTable(
Date,
Time,
MsgLog)
select #Date,
#Time,
#MsgLog
where not exists(
select 1
from MyTable
where (#Date = Date) and
(#Time = Time)
)
P.S. want to delete new one equals to do not insert new one
You should create a unique constraint in the DB level to avoid invalid data no matter who writes to your DB.
It's always important to have your schema well defined. That way you're safe that no matter how many apps are using your DB or even in case someone just writes some inserts manually.
I don't know which DB are you using but in MySQL can use to following DDL
alter table MY_TABLE add unique index(date, time);
And in Oracle you can :
alter table MY_TABLE ADD CONSTRAINT constaint_name UNIQUE (date, time);
That said, you can also (not instead of) do some checks before inserting new values to avoid dealing with exceptions or to improve performance by avoiding making unnecessary access to your DB (length \ nulls for example could easily be dealt with in the application level).
You can avoid deleting by checking for duplicate while inserting.
Just modify your insert procedure like this, so no duplicates will entered.
declare #intCount as int;
select #intCount =count(MsgLog) where (date=#date) and (time =#time )
if #intCount=0
begin
'insert procedure
end
> Edited
since what you wanted is you need to delete the duplicate entries after your bulk insert. Think about this logic,
create a temporary table
Insert LogId,date,time from your table to the temp table order by date,time
now declare four variables, #preTime,#PreDate,#CurrTime,#CurrDate
Loop for each items in temp table, like this
while
begin
#pkLogID= ' Get LogID for the current row
select #currTime=time,#currDate=date from tblTemp where pkLogId=#pkLogID 'Assign Current values
'Delete condition check
if (#currDate=#preDate) and (#currTime=#preTime)
begin
delete from MAINTABLE where pkLogId=#pkLogID
end
select #preDate=#currDate,#preTime=#currTime 'Assign current values as preValues for next entries
end
The above strategy is we sorted all entries according to date and time, so duplicates will come closer, and we started to compare each entry with its previous, when match found we deleting the duplicate entry.
In Sql Server 2008, I have a table that is filled by a data provider application.
I want to keep an "INSERT_DATE" column on table, so that I can know the date the record is inserted.
In order to do this, I defined a default constraint on INSERT_DATE column which puts GETDATE() by default.
However, I don't want this column value to be overwritten by data provider application.
So, how can I disable insert into INSERT_DATE column?
(I cannot use computed column. Because Clustered Index uses INSERT_DATE field)
You could use an After Insert trigger. That way, whatever is inserted into that column for an inserted row you could update to the current date/time.
You probably don't want the column updates as well when the row is subsequently updated.
Your best bet is to use a trigger. You might not be able to throw an error if the application provides a value but at least you will be able to set it right by skipping the column in the insert you specify in your trigger.
I was given a task to display when a record in the database was added, however the previous developers never made a field for this, and I can't go back and make up dates for all the existing records. Is there an easy way to extract out a record Creation date from a SQL server 2000 query.
SELECT RECORD_CREATED_DATE FROM tblSomething WHERE idField = 1
The RECORD_CREATED_DATE isn't a field in the existing table. Is there some sort of SQL Function to get this information ?
If it's not stored as a field, the info is lost after the transaction log recycles (typically daily), and maybe even sooner.
No, unfortunately date of insert or last update are not automatically stored with each record.
To do that, you need to create two datetime columns in your table (e.g. CreatedOn, UpdatedOn) and then in an INSERT trigger set the CreatedOn = getdate() and in the UPDATE trigger set the UpdatedOn = getdate().
CREATE TRIGGER tgr_tblMain_Insert
ON dbo.tblMain
AFTER INSERT
AS
BEGIN
set nocount on
update dbo.tblMain
set CreatedOn = getdate(),
CreatedBy = session_user
where tblMain.ID = INSERTED.ID
END
I also like to create CreatedBy and UpdatedBy varchar(20) columns which I set to session_user or update through other methods.
I would start with putting this information in from now on. Create two columns, InsertedDate, LastUpdatedDate. Use a default value of getdate() on the first and an update trigger to populate the second (might want to consider UpdatedBy as well). Then I would write a query to display the information using the CASE Statement to display the date if there is one and to display "Unknown" is the field is null. This gets more complicated if you need to store a record of all the updates. Then you need to use audit tables.
I'm not aware of a way you can get this information for existing records. However, going forward you can create an audit table that stores the TableName and RecordCreateDate (or something similar.
Then, for the relevant tables you can make an insert trigger:
CREATE TRIGGER trigger_RecordInsertDate
ON YourTableName
AFTER INSERT
AS
BEGIN
-- T-SQL code for inserting a record and timestamp
-- to the audit table goes here
END
create another column and give it a default of getdate() that will take care of inserted date, for updated date you will need to write an update trigger
I have a table in a database that represents dates textually (i.e. "2008-11-09") and I would like to replace them with the UNIX timestamp. However, I don't think that MySQL is capable of doing the conversion on its own, so I'd like to write a little script to do the conversion. The way I can think to do it involves getting all the records in the table, iterating through them, and updating the database records. However, with no primary key, I can't easily get the exact record I need to update.
Is there a way to get MySQL to assign temporary IDs to records during a SELECT so that I refer back to them when doing UPDATEs?
Does this not do it?
UPDATE
MyTable
SET
MyTimeStamp = UNIX_TIMESTAMP(MyDateTime);
If for some reason you do have to iterate (the other answers cover the situation where you don't), I can think of two ways to do it (these aren't MySQL-specific):
Add a column to the table that's an auto-assigned number. Use that as the PK for your updates, then drop the column afterwards (or just keep it around for future use).
In a table with no defined PK, as long as there are no exact duplicate rows, you can use the entire row as a composite PK; just use every column in the row as your distinguishing characteristic. i.e., if the table has 3 columns, "name", "address", and "updated", do the following:
UPDATE mytable SET updated = [timestamp value] WHERE name = [name] AND address = [address] AND timestamp = [old timestamp]
Many data access frameworks use this exact strategy to implement optimistic concurrency.
No, you should be able to do this with a single update statement. If all of the dates are yyyy-mm-dd and they are just stored in some sort of text column instead of DATETIME, you can just move the data over. SQL would be like:
ALTER TABLE t ADD COLUMN dates DATETIME;
UPDATE t set t.dates=t.olddate;
This shouldn't be dependent on a PK because MySQL can scan through each row in the table. The only time PK's become an issue is if you need to update a single row, but the row may not be unique.
You can generate values during a SELECT using the MySQL user variables feature, but these values do not refer to the row; they're temporary parts of the result set only. You can't use them in UPDATE statements.
SET #v := 0;
SELECT #v:=#v+1, * FROM mytable;
Here's how I'd solve the problem. You're going to have to create another column for your UNIX timestamps anyway, so you can add it first. Then convert the values in the old datetime column to the UNIX timestamp and place it in the new column. Then drop the old textual datetime column.
ALTER TABLE mytable ADD COLUMN unix_timestamp INT UNSIGNED NOT NULL DEFAULT 0;
UPDATE mytable
SET unix_timestamp = UNIX_TIMESTAMP( STR_TO_DATE( text_timestamp, '%Y-%m-%d' ) );
ALTER TABLE mytable DROP COLUMN text_timestamp;
Of course you should confirm that the conversion has been done correctly before you drop the old column!
See UNIX_TIMESTAMP() and STR_TO_DATE()