[Chirantan Thakkar]

Hi,

please refer: http://dev.mysql.com/doc/refman/5.0/en/data-type-defaults.html

Quote:

If the column cannot take NULL as the value, MySQL defines the column with an explicit DEFAULT clause, using the implicit default value for the column data type

Prior to MySQL 5.0.2, if a column definition includes no explicit DEFAULT value and the “Not Null” is ticked, then mysql will automatically assign default value to the column based on datatype. So, we can not control it.

By creating a unique index on each column, You can assure a unique value in each column. This will accept NULL for the first time for the column but not again for the same column(ie, MySQL will give you error except for the first time you insert NULL). But again, that will not accept any duplicate value.

[Chirantan Thakkar]

.xmlschema file format is not a standardized format. File with .xmlschema extension is only meant for SQLyog.

But it's a normal XML file so if a program can identify various tags inside the file, obviously it can read the file.

[Chirantan Thakkar]

Hi,

There is no way MySQL provides to get the number of rows going to be affected in advance for the Update Query.

SQLyog just displays the messages returned by the MySQL Server. So until You run the Query, You can not know the number of rows going to be affected.

But You can know the no of rows in advance in another way.

Suppose,

You have an Update Query : Update mytable Set itemname = 'skc' where itemid < 10; Convert it to : SELECT count(*) FROM mytable WHERE itemid < 10;

[Chirantan Thakkar]

Hi,

We use bulk insert to insert data to the target MySQL table. The size of the bulk insert statement will be minimum of max_allowed_packet and 16MB. So you can have a maximum of 16MB data to be inserted/updated at once. The 16MB limit is not configurable.

Also we turn off AUTOCOMMIT when import starts and in the end we are committing the changes. This will affect tables with engines that support transaction (eg: InnoD:cool:. But with non transactional engines like MyISAM, the inserts/updates will be reflected immediately in the target table.

And of course, it's an ODBC import and thus the elements like physical separation, connection type, network speed etc will have significant effect on the time required to complete the import.

[Chirantan Thakkar]

Hi,

Here are the screen-shots..

Please check it..

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