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数据存储组件 · App Inventor 2 中文网
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The callback event for the AddCol block, called once the
values on the table have been updated. Additionally, this returns the
column number for the new column.
FinishedAddRow(rowNumber)
The callback event for the AddRow block, called once the
values on the table have been updated. Additio...
sqlite database default time value 'now'
Is it possible in a sqlite database to craete a table that has a timestamp column that default to DATETIME('now') ?
7 Ans...
delete_all vs destroy_all?
I am looking for the best approach to delete records from a table. For instance, I have a user whose user ID is across many tables. I want to delete this user and every record that has his ID in all tables.
...
Using a .php file to generate a MySQL dump
... or less are auto-explicative:
$dumpSettingsDefault = array(
'include-tables' => array(),
'exclude-tables' => array(),
'compress' => 'None',
'no-data' => false,
'add-drop-database' => false,
'add-drop-table' => false,
'single-transaction' => true,
...
MYSQL OR vs IN performance
...s the same.
$t = microtime(true);
for($i=0; $i<10000; $i++):
$q = DB::table('users')->where('id',1)
->orWhere('id',2)
->orWhere('id',3)
->orWhere('id',4)
->orWhere('id',5)
->orWhere('id',6)
->orWhere('id',7)
->orWhere('id',8)
->orWhere(...
The entity type is not part of the model for the current context
...g(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Estate>().ToTable("Estate");
}
If your tables are not created on startup, this is why. You need to tell the DbContext about them in the OnModelCreating method override.
You can either do custom per-entity mappings here, or separate t...
Is it sometimes bad to use ?
...
Same concept applies to why we don't use tables for layout - use tables for tables and CSS for layout.
Use <br/> for break lines in a block of text and CSS if you want to affect the layout.
...
Why switch is faster than if
...h switch the JVM loads the value to compare and iterates through the value table to find a match, which is faster in most cases.
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Laravel Eloquent ORM Transactions
...ging this.
After reading THIS stackoverflow answer, I realized my database tables were using MyISAM instead of InnoDB.
For transactions to work on Laravel (or anywhere else as it seems), it is required that your tables are set to use InnoDB
Why?
Quoting MySQL Transactions and Atomic Operations docs ...
Still Reachable Leak detected by Valgrind
... reachable" memory can be considered a memory leak: assume you have a hash table where you add pointers to heap allocated memory as value. If you keep inserting new entries on the table, but won't remove and free those you don't need anymore, it can grow indefinitely, leaking heap memory event if th...