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Insert data

  • Статья

You can use SQL statements, either interactively or in source code, to insert one or more rows into tables that are stored in the database.

  • insert method – Insert one row at a time.
  • doInsert method – Insert one row at a time.
  • insert_recordset statement – Copy multiple records directly from one or more tables into another table in one database trip.
  • RecordInsertList.insertDatabase – Insert multiple rows at the same time in one database trip. Use this construct when you don't have to sort the data.
  • RecordSortedList.insertDatabase – Insert multiple rows at the same time in one database trip. Use this construct when you want a subset of data from a specific table, and you want that data to be sorted in an order that doesn't currently exist as an index.

RecordSortedList, RecordInsertList, and insert_recordset let you insert multiple records. By using these methods, you reduce communication between the application and the database. Therefore, you help increase performance. In some situations, record set–based operations can fall back to record-by-record operations. For more information, see Conversion of operations from set-based to record-by-record.

insert method

The insert method inserts one record at a time. It generates values for the RecId field and system fields, and then inserts the contents of the buffer (that is, the column values) into the database.

  • Don't use a select statement on the table variable before you call the insert method.
  • The insert method doesn't handle all the key field requirements and table dependencies. You must write code to handle them.

Here is how the insert method works:

  • Only the specified columns of the rows that have been selected by the query are inserted into the named table.
  • The columns of the table that is copied from and the columns of the table that is copied to must be type-compatible.
  • If the columns of both tables match in type and order, the column list can be omitted from the insert clause.

The following example inserts a new record into the CustGroup table. The CustGroup column of the new record is set to 41. Other fields in the record will be blank.

CustGroup custGroup;
ttsBegin;
custGroup.CustGroup = '41';
custGroup.insert();
ttsCommit;

To override the behavior of the insert method, use the doInsert method.

doInsert method

The doInsert method generates values for the RecId field and other system fields, and then inserts the contents of the buffer into the database. Use this method when the insert method on the table must be bypassed.

Warning

A call to doInsert skips all logic, including database event handlers (for example oninserting and oninserted), chain-of-command onInsert(), and the insert() call itself. It's generally considered bad practice to use doInsert, and we don't recommend that you use it.

insert_recordset statement

The insert_recordset statement copies data directly from one or more source tables into one destination table in one server trip. It's faster to use insert_recordset than an array insert (RecordInsertList.insertDatabase or RecordSortedList.insertDatabase). However, array inserts are more flexible if you want to handle the data before you insert it. Although insert_recordset is a record set–based operator that performs operations on multiple records at a time, it can fall back to record-by-record operations in many situations. For more information, see Conversion of operations from set-based to record-by-record.

In the following syntax for the insert_recordset statement, brackets ([]) indicate optional elements of the statement.

insert_recordset DestinationTable ( ListOfFields )

select ListOfFields1 from SourceTable [ where WhereClause ]

[ join ListOfFields2 from JoinedSourceTable [ where JoinedWhereClause ]]

  • ListOfFields in the destination table must match the list of fields in the source tables. Data is transferred in the order in which it appears in the list of fields. Fields in the destination table that aren't present in the list of fields are assigned 0 (zero) values, as in other areas. System fields, such as RecId, are assigned transparently by the kernel in the destination table.
  • WhereClause and JoinedWhereClause are described in the WhereClause clause in the select statement.

insert_recordset: Inserting data from another table

In this example, the Value column in the NameValuePair table is summed for each Name value. The results of the aggregation are stored in the ValueSumByName table.

ValueSumByName valueSumName;
NameValuePair nameValuePair;

insert_recordset valueSumName (Name, ValueSum)
    select Name, sum(Value)
    from nameValuePair
    group by Name;

insert_recordset: Inserting data from variables

The following example shows that the insert_recordset statement can insert variable data.

  • Include the firstonly keyword to insert only one new record. If you omit firstonly, a record is inserted for each record in the CustTable table.
  • Literals, such as 128 or "this literal string", can't be used in the query as a source of data that is inserted.
  • The columns in the source table don't have to correspond to the target table.

In this example, one new record is inserted into the NameValuePair table. This record has an Id value of 1, a Name value of Name1, and a Value value of 1.

NameValuePair nameValuePair;
CustTable custTable;

int id_var = 1;
str name_var = 'Name1';
int value_var = 1;

insert_recordset nameValuePair (Id, Name, Value)
select firstonly id_var, name_var, value_var from custTable;

insert_recordset: Inserting data by using a join

The following example shows a join of three tables on an insert_recordset statement that has a subselect. It also shows a while select statement that has a similar join. A variable is used to supply the inserted value for one column. The str variable must be declared, and it must have a length that is less than or equal to the maximum length of the corresponding database field.

In this example, there is an insert_recordset statement for the tabEmplProj5 table. One of the target fields is named Description, and its data comes from the local sDescriptionVariable variable. The insert_recordset statement succeeds even when the configuration key for the Description field is turned off. The system ignores both the Description field and the sDescriptionVariable variable. Therefore, this code provides an example of configuration key automation. Configuration key automation occurs when the system can automatically adjust the behavior of an insert_recordset statement that inserts data into fields that the configuration key is turned off for.

static void InsertJoin42Job(Args _args)
{
    GmTabDepartment tabDept2;
    GmTabEmployee tabEmpl3;
    GmTabProject tabProj4;
    GmTabEmployeeProject tabEmplProj5;
    str 64 sDescriptionVariable = "From variable.";
    delete_from tabEmplProj5;
    insert_recordset tabEmplProj5
        (  Description
        , EmployeeRecId
        , ProjectRecId
        )
    select sDescriptionVariable, RecId
    from tabEmpl3
        join tabDept2
            where tabEmpl3 .DepartmentGuid == tabDept2 .DepartmentGuid
        join RecId from tabProj4
            where tabDept2 .DepartmentGuid == tabProj4 .DepartmentGuid;
    info(strFmt("%1 == Number of rows inserted.", tabEmplProj5.rowCount()));        
    
    while select tabEmplProj5
        join tabEmpl3
            where tabEmplProj5.EmployeeRecId == tabEmpl3.RecId
        join tabProj4
            where tabEmplProj5.ProjectRecId == tabProj4.RecId
    {
        info(
            tabEmpl3 .EmployeeName
            + "  --works on--  "
            + tabProj4 .ProjectName
            + " (" + tabEmplProj5 .Description + ")."
            );
    }

/*****************  Actual Infolog output
Message (01:05:41 pm)
4 ==Number of rows inserted.
Alice  --works on--  Project ZZZ (From variable.).
Alice  --works on--  Project YY (From variable.).
Beth  --works on--  Project ZZZ (From variable.).
Beth  --works on--  Project YY (From variable.).
*****************/
}

Handling DuplicateKeyException exceptions

The following example shows how you can catch a DuplicateKeyException exception in the context of an explicit transaction. The exception is thrown when a call to xRecord.insert fails because the key value already exists. In the catch block, your code can either take corrective action or log the error for later analysis. Your code can then continue without losing all the pending work of the transaction. You can't catch a DuplicateKeyException exception that is caused by a set-based operation such as insert_recordset.

This example depends on two tables: SourceTable and DestinationTable. Each table has one mandatory integer field. The fields are named SourceKeyField and DestinationKeyField, respectively. A unique index is defined on each key field. The SourceTable table must have at least one record in it.

static void JobDuplicKeyException44Job(Args _args)
{
    SourceTable      sourceTable; // Must have at least one record.
    DestinationTable destinationTable;
    int countTries = 0;
    int numberAdjust = 0;
    int newKey;
    int inote;
    container notes;

    // Empty the destination table.
    delete_from destinationTable;

    // Copy all the records from SourceTable to DestinationTable
    insert_recordset destinationTable (destinationKeyField)
        select SourceKeyField from sourceTable order by SourceKeyField asc;

    // Copy the records from SourceTable to DestinationTable, one at a time.
    // This immediately throws a DuplicateKeyException.
    ttsBegin;
    try
    {
        countTries++;
        notes += strFmt("Inside the try block, try count is %1.", countTries);
        while select sourceTable 
            order by SourceKeyField asc
        {
            destinationTable.clear();
            newKey = sourceTable.SourceKeyField + numberAdjust;
            destinationTable.DestinationKeyField = newKey;
            notes += strFmt("%1 is the key to be tried." , newKey);
            destinationTable.insert();
            notes += "Success: .insert()";
        }
        ttsCommit;
    }
    catch (Exception::DuplicateKeyException, destinationTable) // Table is optional.
    {
        notes += "Inside the catch block.";
        notes += 'Error: ' + infolog.text().strReplace('\n', '');
        if (countTries <= 1)
        {
            notes += "Will issue retry.";
            numberAdjust = 1;
            retry; // Erases Infolog.
        }
        else
        {
            notes += "Aborting the transaction.";
            ttsAbort;
        }
    }

    for (inote = 1; inote <= conLen(notes); inote++)
    {
        info(conPeek(notes, inote));
    }
}

/* Output
    ---- Inside the try block, try count is 1.
    ---- 11 is the key to be tried.
    ---- Inside the catch block.
    Cannot create a record in DestinationTable (DestinationTable).
    The record already exists.
    ---- Will issue retry.
    ---- Inside the try block, try count is 2.
    ---- 12 is the key to be tried.
    ---- .insert() successful.
*/