A prepared statement is used to efficiently execute a statement multiple times. The Prepared Statement related functions support database failover, which is useful in a replicated database environment, by receiving multiple database profiles.

If a workflow failure occurs using one database profile, a failover process starts to replace that profile with the next available one. If none of the supplied profiles could be used a null value will be returned.

Note!

Failovers can be triggered by all errors that occur while connecting to the database or executing commands, not exclusively due to connection problems.

Please refer to Notes section on the 9. Database Functions page for details on allowed database data type.

sqlPrepSelect

The sqlPrepSelect function is used when selecting data from database tables.

table sqlPrepSelect
    (string sqlStatement,
     any parameter [,...],
     string DBProfile [,...],
	 boolean disableCommit,  //Optional)

Parameter	Description
`sqlStatement`	SQL string containing one or more parameter placeholders ('?').
`parameter(s)`	Value(s) to bind against parameter placeholders.
`DBProfile/s)`	Name of the database profile(s) to use for access.
`disableCommit`	An optional parameter to disable the commit statement from being performed at the end of every SQL transaction for this particular function. Setting this parameter to false will result in the commit statement being performed at the end of every SQL transaction for this particular function. By default, the system will have the disableCommit set to true unless changed by this parameter. It should be noted that on recent Oracle versions, the DBLink SQL transaction behaviour has changed, where every single SQL statement for remote database transactions requires a commit or rollback statement in order to close a connection. In addition, PostgreSQL users should set this to false as every statement needs to be committed.
Returns	Null in case of failure, otherwise a table, holding the SQL select result.

Example - Using sqlPrepSelect

final string sql = "select col2 from tab1 where col1=?"; 
consume {
    table tab = sqlPrepSelect(sql, myUdr.aValue, 
    "Default.myPrimaryDB", "Default.mySecondaryDB");
           
    if ( tab != null ) {
       if ( tableRowCount(tab) > 0 ) {
       	debug("Found following value in col2:" 
       	+ tableGet(tab, 0, 0));
       }
    } 
    else {
      debug("Both primary and secondary database nodes 
             are unavailable");
    }
}

sqlPrepDynamicSelect

The sqlPrepDynamicSelect function is used when selecting data from database tables with dynamically created SQL statements.

table sqlPrepDynamicSelect
    (string sqlStatement,
     list<any> parameters,
     string DBProfile [,...],
	 boolean disableCommit,  //Optional)

Parameter	Description
`sqlStatement`	SQL string containing one or more parameter placeholders ('?'). The string may also contain variables that substitute any part of the statement such as table- or column names. Note! Validation of sqlStatement is performed in runtime and not during configuration. Make sure that number of placeholders matches the actual number of parameters.
`parameter(s)`	Value(s) to bind against parameter placeholders
`DBProfile/s)`	Name of the database profile(s) to use for access
`disableCommit`	An optional parameter to disable the commit statement from being performed at the end of every SQL transaction for this particular function. Setting this parameter to false will result in the commit statement being performed at the end of every SQL transaction for this particular function. By default, the system will have the disableCommit set to true unless otherwise changed via this parameter. It should be noted that on recent Oracle versions, the DBLink SQL transaction behaviour has changed, where every single SQL statement for remote database transactions requires a commit or rollback statement in order to close a connection. In addition, PostgreSQL users should set this to false as every statement needs to be committed.
Returns	Null in case of failure, otherwise a table, holding the SQL select result

Example - Using sqpPrepDynamicSelect

final string EXT_REF_CONFIG = "Default.extrefprop";
string TABLE_KEY = externalReferenceGet(EXT_REF_CONFIG, "mytable");
consume {
        string sql = "select col2 from " + TABLE_KEY + " where col1=?";
        list <any> parameters = listCreate(any, myUDR.aValue);
        table tab = sqlPrepDynamicSelect(sql, parameters, "Default.myPrimaryDB", "Default.mySecondaryDB");
        if ( tab != null ) {
           if ( tableRowCount(tab) > 0 ) {
              debug("Found following value in col2:" + tableGet(tab, 0, 0));
           }
        }
        else {
           abort("Both primary and secondary database nodes are unavailable");
         }
}

sqlPrepUpdate

The sqlPrepUpdate function is used when updating or inserting data into a database table.

int sqlPrepUpdate(
    string sqlStatement,
    any parameter [,...],
    string DBProfile [,...],
    )

Parameter	Description
`sqlStatement`	SQL string containing one or more parameter placeholders ('?')
`parameter(s)`	Value(s) to bind against parameter placeholders
`DBProfile/s)`	Name of the database profile(s) to use for access
Returns	-1 in case of failure, otherwise an integer equal to the number of rows updated or inserted

Example - Using sqpPrepUpdate

final string sql = "update table1 set name = ? where id = ?"; 

consume {
   int cnt = sqlPrepUpdate(sql, aNewName, anIdent, 
    "Default.myPrimaryDB", "Default.mySecondaryDB");
   
   if ( cnt == -1 ) {
       debug("Both primary and secondary database nodes 
    are unavailable");
   }    
}

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