Utility Functions and C Language Reference > Virtual Table Server Functions (VTS) for C, C#, and Java > Virtual Table Server (VTS) Functions for Single Connection > Alphabetical Listing > lrvtc_send_if_unique

lrvtc_send_if_unique

Sets the last field of a column to a value if the value does not exist in the column.

C Language

VTCERR2 lrvtc_send_if_unique ( char *columnName, char *value );

C# Language

void vts.send_if_unique ( string columnName, string value );

Java Language

int Lrvtc.send_if_unique ( string columnName, string value );
Data Update Functions

Arguments

Name Comments
columnName The name of the column.
value The string to write to the field.

lrvtc_send_if_unique sets the last field of a column to a value if the value does not exist in the column. If the value already exists in the column, the function has no effect.

If a column is not indexed, the time required to execute a lrvtc_send_if_unique call increases with the number of rows. If the column is indexed, the time for 'send if unique' operations is constant. For large databases, we recommend that you index columns you want to perform 'send if unique' operations on. See vtc_ensure_index

Return Values

C Language:   Returns zero on success or one of the Error Codes.

C# Language: No return value.

Java Language:   Returns zero on success or one of the Error Codes.

Parameterization

All string input arguments can be passed using standard parameterization.

C Language Example

    int rc;
    ...
    rc = lrvtc_send_if_unique("Default_Answer", "42");
    lr_log_message("Send if unique rc=%d\n", rc);

    

C# Language Example

.Net Single Connection Example

Java Language Example

Java Single Connection Example