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【可动态编辑表格】App Inventor 2 Dynamic Editable HTML Table - App应用...
...lay an AI2 (in csv format e.g. header row, then data rows) list in an html table. It will also allow you (with the exception of the header row) to create new rows, edit any row, and delete any row, whilst returning the saved/updated data to your app, you therefore have a full CRUD.
[co...
Select first row in each GROUP BY group?
...also supports window functions (the CTE needs to be converted to a derived table though). And Firebird 3.0 will also support Window functions
– a_horse_with_no_name
Mar 14 '14 at 9:19
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Postgres: clear entire database before re-creating / re-populating from bash script
...g_dump and pg_restore directly together over a pipe.
To drop and recreate tables, you could use the --clean command-line option for pg_dump to emit SQL commands to clean (drop) database objects prior to (the commands for) creating them. (This will not drop the whole database, just each table/sequen...
How can I get enum possible values in a MySQL database?
...ou. It also strips the quotes from the values.
function get_enum_values( $table, $field )
{
$type = $this->db->query( "SHOW COLUMNS FROM {$table} WHERE Field = '{$field}'" )->row( 0 )->Type;
preg_match("/^enum\(\'(.*)\'\)$/", $type, $matches);
$enum = explode("','", $matches...
nvarchar(max) vs NText
...ld mean some scary long queries where SQL Server would have to rebuild the table and copy everything over, bringing down my websites and raising my heartrate.
I was also concerned that the Linq2SQL could cause errors if it was doing some kind of verification of the column type.
Happy to report tho...
OPTION (RECOMPILE) is Always Faster; Why?
...You hit the nail on the head when you mentioned a query initially run on a table with 10 records, and now the table has millions of records. That was my case exactly. I didn't mention it in the post because I didn't think it mattered. Fascinating stuff. Thanks again.
– Chad Dec...
Why do Lua arrays(tables) start at 1 instead of 0?
...
In Programming in Lua's first discussion of tables, they mention:
Since you can index a table with any value, you can start the indices of an array with any number that pleases you. However, it is customary in Lua to start arrays with 1 (and not with 0, as in C) an...
Do I need to create indexes on foreign keys on Oracle?
I have a table A and a table B . A has a foreign key to B on B 's primary key, B_ID .
7 Answers
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How to convert a string or integer to binary in Ruby?
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Picking up on bta's lookup table idea, you can create the lookup table with a block. Values get generated when they are first accessed and stored for later:
>> lookup_table = Hash.new { |h, i| h[i] = i.to_s(2) }
=> {}
>> lookup_table[1]...
Quick easy way to migrate SQLite3 to MySQL? [closed]
...te_sequence
CREATE UNIQUE INDEX
are not used in MySQL
SQLite uses CREATE TABLE/INSERT INTO "table_name" and MySQL uses CREATE TABLE/INSERT INTO table_name
MySQL doesn't use quotes inside the schema definition
MySQL uses single quotes for strings inside the INSERT INTO clauses
SQLite and MySQL have...