Appendix B. OTL/ODBC, DB2-CLI, accessing system data dictionaries via OTL streams

ODBC / DB2 CLI specifications define functions like SQLTables for accessing system data dictionaries. OTL extends the stream notation for calling the following ODBC / DB2-CLI functions:

SQLColumnPrivileges

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: TableName
Parameter 4: ColumnName

SQLColumns

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: TableName
Parameter 4: ColumnName

SQLForeignKeys

Parameter 1: PKTableCatalog
Parameter 2: PKTableSchema
Parameter 3: PKTableName
Parameter 4: FKTableCatalog
Parameter 5: FKTableSchema
Parameter 6: FKTableName

SQLGetTypeInfo

No parameters

SQLPrimaryKeys

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: TableName

SQLProcedureColumns

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: ProcName
Parameter 4: ColumnName

SQLProcedures

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: ProcName

SQLStatistics

CatalogName
SchemaName
TableName
4th parameter is always SQL_INDEX_ALL

SQLTablePrivileges

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: TableName

SQLTables

Parameter 1: CatalogName
Parameter 2: SchemaName
Parameter 3: TableName
Parameter 4: TableType

The OTL stream extended format is as follows:

$function_name {$1:'val1'} {$2:'val2'} {$3:'val3'} {$4: 'val4'} {$5: 'val5'} {$6: 'val6'}

where {} mean an optional parameter, and $function_name means a name of the ODBC / DB2 CLI functions, listed above. Even though the ODBC and DB2 CLI specifications define the meaning of each ODBC / DB2 CLI function from the list above, in reality, it is specific to every single ODBC / DB2 CLI driver.

Examples

1. "$SQLTables" -- get a list of all tables in the current database.
2. "$SQLTables $1:'%'" -- get a list of all tables in all databases.
3. "$SQLTables $1:'%' $2:'' $3:''" -- get a list of databases on the current connection's server.
4. "$SQLColumns $1:'DMS' $2:'dbo' $3:'test_tab'" -- get a list of all columns of table "test_tab" that belongs to schema "dbo", catalog "DMS".

Here is an example of the full format of the OTL stream extended syntax:

#define OTL_ODBC // or OTL_DB2_CLI
#include <otlv4.h>
...
otl_stream s(100,
               "$SQLTables $1:'%'",
               db);
...
while(!s.eof()){
   s>>...;
}
...

With this new feature (OTL stream extended format), it is possible to use OTL with ODBC data sources that do not have access to their system data dictionaries via normal "system views", which makes it impossible to query the system data dictionary as "SELECT * FROM a system view". Therefore, the only way to query the system data dictionary is via ODBC functions like SQLTables().

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