大约有 41,000 项符合查询结果（耗时：0.0371秒） [XML]
Could not find an implementation of the query pattern
...ed to do it using:
var query = (from p in tblPersoon.Cast<Person>() select p).Single();
This kind of error (Could not find an implementation of the query pattern) usually occurs when:
You are missing LINQ namespace usage (using System.Linq)
Type you are querying does not implement IEnumer...
String is immutable. What exactly is the meaning? [duplicate]
...
A string is a char[] containing a series of UTF-16 code units, an int offset into that array, and an int length.
For example.
String s
It creates space for a string reference. Assigning copies references around but does not modify the...
CASCADE DELETE just once
...you want to cascade.
DELETE FROM some_child_table WHERE some_fk_field IN (SELECT some_id FROM some_Table);
DELETE FROM some_table;
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How to create P12 certificate for iOS distribution
...hain Access where it will be matched up with the private key. You can then select the cert, and open the arrow to also select the private key and export them together as a .p12 file from Keychain Access.
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How to set conditional breakpoints in Visual Studio?
...t a breakpoint.
Right-Click over the breakpoint, and in the popup menu you select an option that suites you.
These options are as follows:
You can set a condition, based on a code expression that you supply (select Condition from the popup menu). For instance, you can specify that foo == 8 or s...
The import javax.servlet can't be resolved [duplicate]
...ibraries tab
Click Add External JARs...
Browse to find servlet-api.jar and select it.
Click OK to update the build path.
Or, if you copy the JAR into your project:
Right-click the project, click Properties.
Choose Java Build Path.
Click Add JARs...
Find servlet-api.jar in your project and select...
Sorting rows in a data table
...
Its Simple Use .Select function.
DataRow[] foundRows=table.Select("Date = '1/31/1979' or OrderID = 2", "CompanyName ASC");
DataTable dt = foundRows.CopyToDataTable();
And it's done......Happy Coding
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How to get size of mysql database?
...
Run this query and you'll probably get what you're looking for:
SELECT table_schema "DB Name",
ROUND(SUM(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB"
FROM information_schema.tables
GROUP BY table_schema;
This query comes from the mysql forums, where there are...
How to change collation of database, table, column?
...he OP asked:
How to change collation of database, table, column?
The selected answer just states it on table level.
Changing it database wide:
ALTER DATABASE <database_name> CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
Changing it per table:
ALTER TABLE <table_name> CON...
Inner join vs Where
... for the query using the inner join:
-- with inner join
EXPLAIN PLAN FOR
SELECT * FROM table1 t1
INNER JOIN table2 t2 ON t1.id = t2.id;
SELECT *
FROM TABLE (DBMS_XPLAN.DISPLAY);
-- 0 select statement
-- 1 hash join (access("T1"."ID"="T2"."ID"))
-- 2 table access full table1
-- 3 table access ful...