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Can a query layer work in a personal database?
Query layers will only work with enterprise databases. File or personal geodatabases are not valid input workspaces for this tool. If the result of the SQL query entered returns a spatial column, the output will be a feature layer. If the SQL query does not return a spatial column, the output will be a stand-alone table.
How to create a new query layer in ArcGIS?
On the New Query Layer dialog box, specify a name in the Name text box for the query layer that will be created. This is the name that will appear in the ArcMap table of contents. Enter an SQL query into the Query text box. Once the query is created, it must be validated.
How to create a data access layer in SQL Server?
The sub-element of the connectionStrings element defines the data source with three different attributes as shown below: providerName – data provider unique name, for example for SQL Server its System.Data.SqlClient and for Oracle its System.Data.OracleClient etc.
Can a data access layer be data provider independent?
I will show how you can make it data provider independent, so that you don’t have to re-write your data access layer if the data storage source changes and also you can reuse it in other applications that you develop.
What happens to the query layer in ArcGIS?
If the result of the SQL query does not return any rows, the output query layer will be empty, only containing the schema of the columns returned by the query. In this case, if the columns returned contain a spatial column the tool will use the following defaults to create the query layer:
How to use dynamic SQL to improve query performance?
A way to speed this up is to use Dynamic SQL, that is generate the SQL statement within the stored procedure and then execute it. SQL Injection can be quite amusing. For example there is a really funny cartoon strip about a mother who has named her son ‘); DROP TABLE Students;– or ‘ Bobby Tables ‘ for short.
How is dynamic SQL used in SQL Server?
Dynamic SQL can be used to speed up the query by simplifying the SQL to the bare minimum, but there are some risks to be avoided. Dynamic SQL is more complicated to write than normal SQL and also harder to debug as the actual SQL statement that is executed is not easily visible.