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Usage of uniqueResult

uniqueResult is a method in the Hibernate framework that is used to execute queries and return unique results. Whether using HQL or the Criteria API, you can use the uniqueResult method to get unique results. When using this method, you need to ensure the uniqueness of the query results to avoid exceptions being thrown.

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uniqueresult oracle distinct mysql mysql wildcard typedef usage typedef linux grep groupby

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Usage of uniqueResult

What is the usage of uniqueResult?

Sep 15, 2023 pm 05:26 PM

uniqueresult

What is the usage of oracle distinct

Oracle's distinct usage can filter duplicate rows in the result set to ensure that the value of the specified column or columns returned in the "SELECT" clause is unique. The syntax is "SELECT DISTINCT column 1, column 2, column 3... from table name". "distinct" will sort the returned result set and can be used in conjunction with "order by" to improve efficiency.

Sep 05, 2023 am 09:47 AM

oracle distinct

What are the uses of mysql wildcards?

The usage of wildcard characters in MySQL includes percent sign (%) and underscore (_). Detailed introduction: 1. The wildcard percent sign (%) can query data starting with a specific character, query data ending with a specific character, and query data containing specific characters; 2. Underscore (_) can query the second character as a specific character. Character data, query the data when the third character is a specific character, query the data when the fourth character is a specific character.

Sep 15, 2023 am 11:49 AM

mysql mysql wildcard

What is the usage of typedef

The use of typedef is to create new aliases for existing data types. Using typedefs can increase the readability and maintainability of your code, especially when dealing with complex data types. For simple data types, such as integers, floating point numbers, or characters, the benefits of using aliases are not obvious. However, for complex data types such as pointers, structures, arrays, and functions, the advantages of using aliases are obvious. A typedef cannot be used before a variable or function definition and is usually created at the top of a program file or after a structure definition.

Sep 04, 2023 pm 01:20 PM

typedef usage typedef

What is the usage of grep in linux?

The usage of grep in Linux is to search for lines of text that match a specific pattern and output the matching lines. The grep command has a variety of options and usages, allowing flexible search and matching operations according to different needs. Commonly used options are: 1. -i, ignore the case of characters when searching; 2. -n, display matching line numbers; 3. -c, count the number of matching lines; 4. -r, recursively search in the specified directory Search files under; 5. -l, only display file names containing matching items; 6. -v, reverse matching, output lines that do not contain matching items, etc.

Sep 04, 2023 pm 01:55 PM

linux grep

How to use the groupby function

The usage of the groupby function is "DataFrame.groupby(by=None, axis=0, level=None, as_index=True, sort=True, group_keys=True, squeeze=False, observed=False, dropna=True)". The groupby function is a common data processing function used to group data.

Sep 12, 2023 am 10:47 AM

groupby