SQLOLEDB exposes ITableDefinition::CreateTable allowing consumers to create SQL Server tables. Consumers use CreateTable to create consumer-named permanent and temporary tables, and permanent or temporary tables with unique names generated by SQLOLEDB.
When consumers specify the table name in the pwszName member of the uName union in the pTableID parameter, SQLOLEDB creates a SQL Server table with that name. SQL Server table naming constraints apply, and the table name can indicate a permanent table or either a local or global temporary table. For more information, see CREATE TABLE. The ppTableID parameter can be NULL.
SQLOLEDB can generate the names of permanent or temporary tables. When the consumer sets the pTableID parameter to NULL and sets ppTableID to point to a valid DBID*, SQLOLEDB returns the generated name of the table in the pwszName member of the uName union of the DBID pointed to by the value of ppTableID. To create a temporary, SQLOLEDB-named table, the consumer includes the OLE DB table property DBPROP_TBL_TEMPTABLE in a table property set referenced in the rgPropertySets parameter. SQLOLEDB-named temporary tables are local. For more information, see CREATE TABLE.
CreateTable returns DB_E_BADID if the eKind member of the pTableID parameter does not indicate DBKIND_NAME.
The consumer can indicate a column data type by using either the pwszTypeName member or the wType member. If the consumer specifies the data type in pwszTypeName, SQLOLEDB ignores the value of wType.
If using the pwszTypeName member, the consumer specifies the data type by using SQL Server data type names. Valid data type names are returned in the TYPE_NAME column of the PROVIDER_TYPES schema rowset.
SQLOLEDB recognizes a subset of OLE DB-enumerated DBTYPE values in the wType member. For more information, see Data Type Mapping in ITableDefinition.
CreateTable returns DB_E_BADTYPE if consumer sets either the pTypeInfo or pclsid member to specify the column data type.
The consumer specifies the column name in the pwszName member of the uName union of the DBCOLUMNDESC dbcid member. The column name is specified as a Unicode character string. The eKind member of dbcid must be DBKIND_NAME. CreateTable returns DB_E_COLUMNID if eKind is invalid, pwszName is NULL, or if the value of pwszName is not a valid SQL Server identifier.
All column properties are available on all columns defined for the table. CreateTable can return DB_S_ERRORSOCCURRED if property values are set in conflict. CreateTable returns an error when invalid column property settings cause SQL Server table-creation failure.
Column properties in a DBCOLUMNDESC are interpreted as follows.
| Property ID | Description |
| DBPROP_COL_ AUTOINCREMENT |
R/W: Read/write Default: VARIANT_FALSE Description: Sets the identity property on the column created. For SQL Server, the identity property is valid for a single column within a table. Setting the property to VARIANT_TRUE for more than a single column generates an error when SQLOLEDB attempts to create the table on the server. The SQL Server identity property is only valid for the integral types and the numeric and decimal types when the scale is 0. Setting the property to VARIANT_TRUE on a column of any other data type generates an error when SQLOLEDB attempts to create the table on the server.
SQLOLEDB returns DB_S_ |
| DBPROP_COL_DEFAULT | R/W: Read/write Default: None Description: Creates a SQL Server DEFAULT constraint for the column. The vValue DBPROP member can be any of a number of types. The vValue.vt member should specify a type compatible with the data type of the column. For example, defining the BSTR N/A as the default value for a column defined as DBTYPE_WSTR is a compatible match. Defining the same default on a column defined as DBTYPE_R8 generates an error when SQLOLEDB attempts to create the table on the server. |
| DBPROP_COL_DESCRIPTION | R/W: Read/write Default: None Description: The DBPROP_COL_ DESCRIPTION column property is not implemented by SQLOLEDB.
The dwStatus member of the DBPROP structure returns DBPROPSTATUS_ Setting the property does not constitute a fatal error for SQLOLEDB. If all other parameter values are valid, the SQL Server table is created. |
| DBPROP_COL_FIXEDLENGTH | R/W: Read/write Default: VARIANT_FALSE Description: SQLOLEDB uses DBPROP_ COL_FIXEDLENGTH to determine data type-mapping when the consumer defines a column’s data type by using the wType member of the DBCOLUMNDESC. For more information, see Data Type Mapping in ITableDefinition. |
| DBPROP_COL_NULLABLE | R/W: Read/write Default: None Description: When creating the table, SQLOLEDB indicates whether the column should accept null values if the property is set. When the property is not set, the ability of the column to accept NULL as a value is determined by the SQL Server ANSI NULL default database option. SQLOLEDB is an ANSI SQL-compliant provider. Connected sessions exhibit ANSI behaviors. If the consumer does not set DBPROP_COL_NULLABLE, columns accept null values. |
| DBPROP_COL_PRIMARYKEY | R/W: Read/write Default: VARIANT_FALSE Description: When VARIANT_TRUE, SQLOLEDB creates the column with a primary key constraint. When defined as a column property, only a single column can determine the constraint. Setting the property VARIANT_TRUE for more than a single column returns an error when SQLOLEDB attempts to create the SQL Server table. Note The consumer can use IIndexDefinition::CreateIndex to create a primary key constraint on two or more columns.
SQLOLEDB returns DB_S_
SQLOLEDB returns an error when DBPROP_ SQLOLEDB returns an error from SQL Server when the consumer attempts to create a primary key constraint on a column of invalid SQL Server data type. Primary key constraints cannot be defined on columns created with the SQL Server data types bit, text, ntext, and image. |
| DBPROP_COL_UNIQUE | R/W: Read/write Default: VARIANT_FALSE Description: Applies a SQL Server unique constraint to the column.
When defined as a column property, the constraint is applied on a single column only. The consumer can use IIndexDefinition::
SQLOLEDB returns DB_S_
SQLOLEDB returns DB_S_ SQLOLEDB returns an error from SQL Server when the consumer attempts to create a unique constraint on a column of invalid SQL Server data type. Unique constraints cannot be defined on columns created with the SQL Server data type bit. |
When the consumer calls ITableDefinition::CreateTable, SQLOLEDB interprets table properties as follows.
| Property ID | Description |
| DBPROP_TBL_TEMPTABLE | R/W: Read/write Default: VARIANT_FALSE Description: By default, SQLOLEDB creates tables named by the consumer. When VARIANT_TRUE, SQLOLEDB generates a temporary table name for the consumer. The consumer sets the pTableID parameter of CreateTable to NULL. The ppTableID parameter must contain a valid pointer. |
If the consumer requests that a rowset be opened on a successfully created table, SQLOLEDB opens a cursor-supported rowset. Any rowset properties can be indicated in the property sets passed.
This example creates a SQL Server table.
////////////////////////////////////////////////////////////////////////
// Create the OrderDetails table as follows:
//
// CREATE TABLE OrderDetails
// (
// OrderID int NOT NULL
// ProductID int NOT NULL
// CONSTRAINT PK_OrderDetails
// PRIMARY KEY CLUSTERED (OrderID, ProductID),
// UnitPrice money NOT NULL,
// Quantity int NOT NULL,
// Discount decimal(2,2) NOT NULL
// DEFAULT 0
// )
//
// The primary key constraint is created in an additional example.
HRESULT CreateTable
(
ITableDefinition* pITableDefinition
)
{
DBID dbidTable;
const ULONG nCols = 5;
ULONG nCol;
ULONG nProp;
DBCOLUMNDESC dbcoldesc[nCols];
HRESULT hr;
// Set up column descriptions. First set default property values for
// the columns.
for (nCol = 0; nCol < nCols; nCol++)
{
dbcoldesc[nCol].pwszTypeName = NULL;
dbcoldesc[nCol].pTypeInfo = NULL;
dbcoldesc[nCol].rgPropertySets = new DBPROPSET;
dbcoldesc[nCol].pclsid = NULL;
dbcoldesc[nCol].cPropertySets = 1;
dbcoldesc[nCol].ulColumnSize = 0;
dbcoldesc[nCol].dbcid.eKind = DBKIND_NAME;
dbcoldesc[nCol].wType = DBTYPE_I4;
dbcoldesc[nCol].bPrecision = 0;
dbcoldesc[nCol].bScale = 0;
dbcoldesc[nCol].rgPropertySets[0].rgProperties =
new DBPROP[NCOLPROPS_MAX];
dbcoldesc[nCol].rgPropertySets[0].cProperties = NCOLPROPS_MAX;
dbcoldesc[nCol].rgPropertySets[0].guidPropertySet =
DBPROPSET_COLUMN;
for (nProp = 0; nProp < NCOLPROPS_MAX; nProp++)
{
dbcoldesc[nCol].rgPropertySets[0].rgProperties[nProp].
dwOptions = DBPROPOPTIONS_REQUIRED;
dbcoldesc[nCol].rgPropertySets[0].rgProperties[nProp].colid
= DB_NULLID;
VariantInit(
&(dbcoldesc[nCol].rgPropertySets[0].rgProperties[nProp].
vValue));
dbcoldesc[nCol].rgPropertySets[0].rgProperties[nProp].
vValue.vt = VT_BOOL;
}
}
// Set the column-specific information.
dbcoldesc[0].dbcid.uName.pwszName = L"OrderID";
dbcoldesc[0].rgPropertySets[0].rgProperties[0].dwPropertyID =
DBPROP_COL_NULLABLE;
dbcoldesc[0].rgPropertySets[0].rgProperties[0].vValue.boolVal =
VARIANT_FALSE;
dbcoldesc[0].rgPropertySets[0].cProperties = 1;
dbcoldesc[1].dbcid.uName.pwszName = L"ProductID";
dbcoldesc[1].rgPropertySets[0].rgProperties[0].dwPropertyID =
DBPROP_COL_NULLABLE;
dbcoldesc[1].rgPropertySets[0].rgProperties[0].vValue.boolVal =
VARIANT_FALSE;
dbcoldesc[1].rgPropertySets[0].cProperties = 1;
dbcoldesc[2].dbcid.uName.pwszName = L"UnitPrice";
dbcoldesc[2].wType = DBTYPE_CY;
dbcoldesc[2].rgPropertySets[0].rgProperties[0].dwPropertyID =
DBPROP_COL_NULLABLE;
dbcoldesc[2].rgPropertySets[0].rgProperties[0].vValue.boolVal =
VARIANT_FALSE;
dbcoldesc[2].rgPropertySets[0].cProperties = 1;
dbcoldesc[3].dbcid.uName.pwszName = L"Quantity";
dbcoldesc[3].rgPropertySets[0].rgProperties[0].dwPropertyID =
DBPROP_COL_NULLABLE;
dbcoldesc[3].rgPropertySets[0].rgProperties[0].vValue.boolVal =
VARIANT_FALSE;
dbcoldesc[3].rgPropertySets[0].cProperties = 1;
dbcoldesc[4].dbcid.uName.pwszName = L"Discount";
dbcoldesc[4].wType = DBTYPE_NUMERIC;
dbcoldesc[4].bPrecision = 2;
dbcoldesc[4].bScale = 2;
dbcoldesc[4].rgPropertySets[0].rgProperties[0].dwPropertyID =
DBPROP_COL_NULLABLE;
dbcoldesc[4].rgPropertySets[0].rgProperties[0].vValue.boolVal =
VARIANT_FALSE;
dbcoldesc[4].rgPropertySets[0].rgProperties[1].dwPropertyID =
DBPROP_COL_DEFAULT;
dbcoldesc[4].rgPropertySets[0].rgProperties[1].vValue.vt = VT_BSTR;
dbcoldesc[4].rgPropertySets[0].rgProperties[1].vValue.bstrVal =
SysAllocString(L"0");
dbcoldesc[4].rgPropertySets[0].cProperties = 2;
// Set up the dbid for OrderDetails.
dbidTable.eKind = DBKIND_NAME;
dbidTable.uName.pwszName = L"OrderDetails";
if (FAILED(hr = pITableDefinition->CreateTable(NULL, &dbidTable,
nCols, dbcoldesc, NULL, 0, NULL, NULL, NULL)))
{
DumpError(pITableDefinition, IID_ITableDefinition);
goto SAFE_EXIT;
}
SAFE_EXIT:
// Clean up dynamic allocation in the property sets.
for (nCol = 0; nCol < nCols; nCol++)
{
for (nProp = 0; nProp < NCOLPROPS_MAX; nProp++)
{
if (dbcoldesc[nCol].rgPropertySets[0].rgProperties[nProp].
vValue.vt == VT_BSTR)
{
SysFreeString(dbcoldesc[nCol].rgPropertySets[0].
rgProperties[nProp].vValue.bstrVal);
}
}
delete [] dbcoldesc[nCol].rgPropertySets[0].rgProperties;
delete [] dbcoldesc[nCol].rgPropertySets;
}
return (hr);
}
See Also