Contents
Do Queries hold data?
Query Store stores its data inside the user database and that is why it has size limit (configured with MAX_STORAGE_SIZE_MB ). If data in Query Store hits that limit Query Store will automatically change state from read-write to read-only and stop collecting new data.
What it means to query data?
A query is a request for data or information from a database table or combination of tables. This data may be generated as results returned by Structured Query Language (SQL) or as pictorials, graphs or complex results, e.g., trend analyses from data-mining tools.
Why are queries used in databases?
Queries can perform many different functions in a database. Their most common function is to retrieve specific data from the tables. The data you want to see is usually spread across several tables, and queries allow you to view it in a single datasheet.
Why do we use query?
Using a query makes it easier to view, add, delete, or change data in your Access database. Some other reasons for using queries: Find specific quickly data by filtering on specific criteria (conditions) Calculate or summarize data.
How to query a dataset using LINQ to dataset?
Querying DataSets (LINQ to DataSet) After a DataSet object has been populated with data, you can begin querying it. Formulating queries with LINQ to DataSet is similar to using Language-Integrated Query (LINQ) against other LINQ-enabled data sources.
How to query a dataset in Visual Studio?
The code examples use typed DataRow s ( NorthwindDataSet.OrdersRow) and the generated FindBy PrimaryKey ( FindByCustomerID) methods to locate a desired row and return the related records. The examples compile and run correctly only if you have: An instance of a dataset named NorthwindDataSet with a Customers table.
How to search for specific records in a dataset?
To search for specific records in a dataset, use the FindBy method on the DataTable, write your own foreach statement to loop over the table’s Rows collection, or use LINQ to DataSet. Within a dataset, table and column names are case-insensitive by default — that is, a table in a dataset called “Customers” can also be referred to as “customers.”
Why are data elements not distinguished by case in SQL?
This matches the naming conventions in many databases, including SQL Server. In SQL Server, the default behavior is that the names of data elements cannot be distinguished only by case. Unlike datasets, XML documents are case-sensitive, so the names of data elements defined in schemas are case-sensitive.