MongoDB provides several ways to drop an index or indexes.
To drop a single index, you can use the dropIndex() method.
To drop multiple indexes, you can use either the dropIndexes() method or the dropIndexes administration command.
Category: DBMS
Database Management Systems
How MATCH AGAINST Works in MariaDB
In MariaDB, MATCH AGAINST is a special construct used to perform a full-text search on a full-text index.
How COERCIBILITY() Works in MariaDB
In MariaDB, COERCIBILITY() is a system function that returns the collation coercibility value of its string argument.
It defines how collations will be converted in the case of collation conflict. In such conflicts, an expression with a higher coercibility is converted to the collation of an expression with a lower coercibility.
Continue readingHow to Set MariaDB to use Vertical Output
If you connect to MariaDB using the command line interface, you might sometimes find that your query results are too wide, due to the number of columns being returned, and the data they contain.
Continue readingHow MAKE_SET() Works in MariaDB
In MariaDB, MAKE_SET() is a string function that returns a set value, based on the values provided in its arguments.
A set is a string containing substrings separated by comma (,) characters.
How TRIM_ORACLE() Works in MariaDB
In MariaDB, TRIM_ORACLE() is a synonym for the Oracle mode version of the TRIM() function.
TRIM_ORACLE() is available in all modes, so it saves you from having to switch to Oracle mode, which is what you’d need to do if you wanted the TRIM() function to behave like Oracle’s TRIM() function.
The difference is in how each function treats empty strings. Oracle returns null whereas MariaDB returns an empty string.
How LTRIM_ORACLE() Works in MariaDB
In MariaDB, LTRIM_ORACLE() is a synonym for the Oracle mode version of the LTRIM() function.
LTRIM_ORACLE() is available in all modes, so it saves you from having to switch to Oracle mode, which is what you’d need to do if you wanted the LTRIM() function to behave like Oracle’s LTRIM() function.
The difference is in how each function treats empty strings. Oracle returns null whereas MariaDB returns an empty string.
How RTRIM_ORACLE() Works in MariaDB
In MariaDB, RTRIM_ORACLE() is a synonym for the Oracle mode version of the RTRIM() function.
RTRIM_ORACLE() is available in all modes, so it saves you from having to switch to Oracle mode, which is what you’d need to do if you wanted the RTRIM() function to behave like Oracle’s RTRIM() function.
The difference is in how each function treats empty strings. Oracle returns null whereas MariaDB returns an empty string.
How EXTRACTVALUE() Works in MariaDB
In MariaDB, EXTRACTVALUE() is a built-in string function that returns CDATA from an XML fragment.
The way it works is that it accepts two string arguments: a fragment of XML markup and an XPath expression (i.e. a locator). EXTRACTVALUE() then returns the CDATA (i.e. the text) of the first text node which is a child of the element or elements matching the XPath expression.
How TRIM() Works in MariaDB
In MariaDB, TRIM() is a built-in string function that removes characters from the start or end of a string.
By default it removes leading and trailing spaces, but you can specify which character to remove, as well as which side/s you’d like it removed from.
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