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I have a bit IsDefault column. Only one row of data within the table may have this bit column set to 1, all the others must be 0.
How can I enforce this?
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If there are from 9 up to 16 bit columns, the columns are stored as 2 bytes, and so on. The string values TRUE and FALSE can be converted to bit values: TRUE is converted to 1 and FALSE is converted to 0. Converting to bit promotes any nonzero value to 1.
SQL Server bit data type is an integer data type that can take only one of these values: 0, 1, NULL. With regard to the storage, if there are less than 9 columns of the bit data in the table, they are stored as 1 byte. If there are 9 to 16 such columns, they consume 2 bytes and so on.
SQL Server BIT data type is an integer data type that can take a value of 0, 1, or NULL . The following illustrates the syntax of the BIT data type: BIT. SQL Server optimizes storage of BIT columns. If a table has 8 or fewer bit columns, SQL Server stores them as 1 byte.
In this case, we use GROUP_CONCAT function to concatenate multiple rows into one column. GROUP_CONCAT concatenates all non-null values in a group and returns them as a single string. If you want to avoid duplicates, you can also add DISTINCT in your query.
All versions:
SQL Server 2008: a filtered index
CREATE UNIQUE INDEX IX_foo ON bar (MyBitCol) WHERE MyBitCol = 1 If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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