✏️ Explanatory Question
The second type of temporary table is the InMemory table. We call them InMemory tables because their TableType property value is InMemory. This value comes from the TableType::InMemory enum value. The TableType property value can be seen at AOT > Data Dictionary > Tables > MyInMemoryTable > Properties > TableType.
Note: In Microsoft Dynamics AX 2009 and earlier versions, InMemory tables were called temporary tables. Now there are two kinds of temporary tables, namely InMemory tables and TempDB tables. To avoid confusion we do not use the phrase temporary tables to refer to just InMemory tables or to just TempDB tables.
Tier: InMemory tables are instantiated in the active memory of whichever tier the process is running on, either the client or the server tier. InMemory tables are never represented in the database management system.
An InMemory table is held in memory until its size reaches 128 KB. The dataset is then written to a disk file on the server tier.
Scope: An InMemory table is instantiated when the first record is inserted. The instantiated InMemory table continues to exist only while a record buffer variable that references the table exists. The memory or disk space for the InMemory table is de-allocated as soon as the record buffer goes out of scope.
Indexes: can be defined on an InMemory table just as you would a persisted table. If an InMemory table is created by copying a persisted table, the indexes are also copied to the InMemory table. Indexes are useful for quickly retrieving data from InMemory tables, especially if the InMemory table data is in a disk file.
static void Aj_MyInMemoryTableUsage1()
{
Aj_MyInMemoryTable custTmpLedger;
custTmpLedger.Name = 'customer tmp 1';
custTmpLedger.AccountNUm = "C0000001";
custTmpLedger.insert();
while select custTmpLedger
{
info(strFmt("Name: %1, AcccountNUm: %2", custTmpLedger.Name, custTmpLedger.AccountNUm));
}
custTmpLedger = null;
}