SQLStatistics Function
Conformance
Version Introduced: ODBC 1.0 Standards Compliance: ISO 92
Summary
SQLStatistics retrieves a list of statistics about a single table and the indexes associated with the table. The driver returns the information as a result set.
Syntax
SQLRETURN SQLStatistics(
SQLHSTMT StatementHandle,
SQLCHAR * CatalogName,
SQLSMALLINT NameLength1,
SQLCHAR * SchemaName,
SQLSMALLINT NameLength2,
SQLCHAR * TableName,
SQLSMALLINT NameLength3,
SQLUSMALLINT Unique,
SQLUSMALLINT Reserved);
Arguments
StatementHandle
[Input] Statement handle.
CatalogName
[Input] Catalog name. If a driver supports catalogs for some tables but not for others, such as when the driver retrieves data from different DBMSs, an empty string ("") indicates those tables that do not have catalogs. CatalogName cannot contain a string search pattern.
If the SQL_ATTR_METADATA_ID statement attribute is set to SQL_TRUE, CatalogName is treated as an identifier and its case is not significant. If it is SQL_FALSE, CatalogName is an ordinary argument; it is treated literally, and its case is significant. For more information, see Arguments in Catalog Functions.
NameLength1
[Input] Length in characters of *CatalogName.
SchemaName
[Input] Schema name. If a driver supports schemas for some tables but not for others, such as when the driver retrieves data from different DBMSs, an empty string ("") indicates those tables that do not have schemas. SchemaName cannot contain a string search pattern.
If the SQL_ATTR_METADATA_ID statement attribute is set to SQL_TRUE, SchemaName is treated as an identifier and its case is not significant. If it is SQL_FALSE, SchemaName is an ordinary argument; it is treated literally, and its case is significant.
NameLength2
[Input] Length in characters of *SchemaName.
TableName
[Input] Table name. This argument cannot be a null pointer. SchemaName cannot contain a string search pattern.
If the SQL_ATTR_METADATA_ID statement attribute is set to SQL_TRUE, TableName is treated as an identifier and its case is not significant. If it is SQL_FALSE, TableName is an ordinary argument; it is treated literally, and its case is significant.
NameLength3
[Input] Length in characters of *TableName.
Unique
[Input] Type of index: SQL_INDEX_UNIQUE or SQL_INDEX_ALL.
Reserved
[Input] Indicates the importance of the CARDINALITY and PAGES columns in the result set. The following options affect the return of the CARDINALITY and PAGES columns only; index information is returned even if CARDINALITY and PAGES are not returned.
SQL_ENSURE requests that the driver unconditionally retrieve the statistics. (Drivers that conform only to the Open Group standard and do not support ODBC extensions will not be able to support SQL_ENSURE.)
SQL_QUICK requests that the driver retrieve the CARDINALITY and PAGES only if they are readily available from the server. In this case, the driver does not ensure that the values are current. (Applications that are written to the Open Group standard will always get SQL_QUICK behavior from ODBC 3.x-compliant drivers.)
Returns
SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_STILL_EXECUTING, SQL_ERROR, or SQL_INVALID_HANDLE.
Diagnostics
When SQLStatistics returns SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value can be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_STMT and a Handle of StatementHandle. The following table lists the SQLSTATE values typically returned by SQLStatistics and explains each one in the context of this function; the notation "(DM)" precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.
| SQLSTATE | Error | Description |
|---|---|---|
| 01000 | General warning | Driver-specific informational message. (Function returns SQL_SUCCESS_WITH_INFO.) |
| 08S01 | Communication link failure | The communication link between the driver and the data source to which the driver was connected failed before the function completed processing. |
| 24000 | Invalid cursor state | A cursor was open on the StatementHandle, and SQLFetch or SQLFetchScroll had been called. This error is returned by the Driver Manager if SQLFetch or SQLFetchScroll has not returned SQL_NO_DATA and is returned by the driver if SQLFetch or SQLFetchScroll has returned SQL_NO_DATA. A cursor was open on the StatementHandle, but SQLFetch or SQLFetchScroll had not been called. |
| 40001 | Serialization failure | The transaction was rolled back because of a resource deadlock with another transaction. |
| 40003 | Statement completion unknown | The associated connection failed during the execution of this function, and the state of the transaction cannot be determined. |
| HY000 | General error | An error occurred for which there was no specific SQLSTATE and for which no implementation-specific SQLSTATE was defined. The error message returned by SQLGetDiagRec in the *MessageText buffer describes the error and its cause. |
| HY001 | Memory allocation error | The driver was unable to allocate memory that is required to support execution or completion of the function. |
| HY008 | Operation canceled | Asynchronous processing was enabled for the StatementHandle. The function was called, and before it completed execution, SQLCancel or SQLCancelHandle was called on the StatementHandle, and then the function was called again on the StatementHandle. The function was called, and before it completed execution, SQLCancel or SQLCancelHandle was called on the StatementHandle from a different thread in a multithread application. |
| HY009 | Invalid use of null pointer | The TableName argument was a null pointer. The SQL_ATTR_METADATA_ID statement attribute was set to SQL_TRUE, the CatalogName argument was a null pointer, and the SQL_CATALOG_NAME InfoType returns that catalog names are supported. (DM) The SQL_ATTR_METADATA_ID statement attribute was set to SQL_TRUE, and the SchemaName argument was a null pointer. |
| HY010 | Function sequence error | (DM) An asynchronously executing function was called for the connection handle that is associated with the StatementHandle. This asynchronous function was still executing when the SQLStatistics function was called. (DM) SQLExecute, SQLExecDirect, or SQLMoreResults was called for the StatementHandle and returned SQL_PARAM_DATA_AVAILABLE. This function was called before data was retrieved for all streamed parameters. (DM) An asynchronously executing function (not this one) was called for the StatementHandle and was still executing when this function was called. (DM) SQLExecute, SQLExecDirect, SQLBulkOperations, or SQLSetPos was called for the StatementHandle and returned SQL_NEED_DATA. This function was called before data was sent for all data-at-execution parameters or columns. |
| HY013 | Memory management error | The function call could not be processed because the underlying memory objects could not be accessed, possibly because of low memory conditions. |
| HY090 | Invalid string or buffer length | (DM) The value of one of the name length arguments was less than 0 but not equal to SQL_NTS. The value of one of the name length arguments exceeded the maximum length value for the corresponding name. |
| HY100 | Uniqueness option type out of range | (DM) An invalid Unique value was specified. |
| HY101 | Accuracy option type out of range | (DM) An invalid Reserved value was specified. |
| HY117 | Connection is suspended due to unknown transaction state. Only disconnect and read-only functions are allowed. | (DM) For more information about suspended state, see SQLEndTran Function. |
| HYC00 | Optional feature not implemented | A catalog was specified, and the driver or data source does not support catalogs. A schema was specified, and the driver or data source does not support schemas. The combination of the current settings of the SQL_ATTR_CONCURRENCY and SQL_ATTR_CURSOR_TYPE statement attributes was not supported by the driver or data source. The SQL_ATTR_USE_BOOKMARKS statement attribute was set to SQL_UB_VARIABLE, and the SQL_ATTR_CURSOR_TYPE statement attribute was set to a cursor type for which the driver does not support bookmarks. |
| HYT00 | Timeout expired | The query timeout period expired before the data source returned the requested result set. The timeout period is set through SQLSetStmtAttr, SQL_ATTR_QUERY_TIMEOUT. |
| HYT01 | Connection timeout expired | The connection timeout period expired before the data source responded to the request. The connection timeout period is set through SQLSetConnectAttr, SQL_ATTR_CONNECTION_TIMEOUT. |
| IM001 | Driver does not support this function | (DM) The driver associated with the StatementHandle does not support the function. |
| IM017 | Polling is disabled in asynchronous notification mode | Whenever the notification model is used, polling is disabled. |
| IM018 | SQLCompleteAsync has not been called to complete the previous asynchronous operation on this handle. | If the previous function call on the handle returns SQL_STILL_EXECUTING and if notification mode is enabled, SQLCompleteAsync must be called on the handle to do post-processing and complete the operation. |
Comments
SQLStatistics returns information about a single table as a standard result set, ordered by NON_UNIQUE, TYPE, INDEX_QUALIFIER, INDEX_NAME, and ORDINAL_POSITION. The result set combines statistics information (in the CARDINALITY and PAGES columns of the result set) for the table with information about each index. For information about how this information might be used, see Uses of Catalog Data.
To determine the actual lengths of the TABLE_CAT, TABLE_SCHEM, TABLE_NAME, and COLUMN_NAME columns, an application can call SQLGetInfo with the SQL_MAX_CATALOG_NAME_LEN, SQL_MAX_SCHEMA_NAME_LEN, SQL_MAX_TABLE_NAME_LEN, and SQL_MAX_COLUMN_NAME_LEN options.
Note
For more information about the general use, arguments, and returned data of ODBC catalog functions, see Catalog Functions.
The following columns have been renamed for ODBC 3.x. The column name changes do not affect backward compatibility because applications bind by column number.
| ODBC 2.0 column | ODBC 3.x column |
|---|---|
| TABLE_QUALIFIER | TABLE_CAT |
| TABLE_OWNER | TABLE_SCHEM |
| SEQ_IN_INDEX | ORDINAL_POSITION |
| COLLATION | ASC_OR_DESC |
The following table lists the columns in the result set. Additional columns beyond column 13 (FILTER_CONDITION) can be defined by the driver. An application should gain access to driver-specific columns by counting down from the end of the result set instead of specifying an explicit ordinal position. For more information, see Data Returned by Catalog Functions.
| Column name | Column number | Data type | Comments |
|---|---|---|---|
| TABLE_CAT (ODBC 1.0) | 1 | Varchar | Catalog name of the table to which the statistic or index applies; NULL if not applicable to the data source. If a driver supports catalogs for some tables but not for others, such as when the driver retrieves data from different DBMSs, it returns an empty string ("") for those tables that do not have catalogs. |
| TABLE_SCHEM (ODBC 1.0) | 2 | Varchar | Schema name of the table to which the statistic or index applies; NULL if not applicable to the data source. If a driver supports schemas for some tables but not for others, such as when the driver retrieves data from different DBMSs, it returns an empty string ("") for those tables that do not have schemas. |
| TABLE_NAME (ODBC 1.0) | 3 | Varchar not NULL | Table name of the table to which the statistic or index applies. |
| NON_UNIQUE (ODBC 1.0) | 4 | Smallint | Indicates whether the index does not allow duplicate values: SQL_TRUE if the index values can be nonunique. SQL_FALSE if the index values must be unique. NULL is returned if TYPE is SQL_TABLE_STAT. |
| INDEX_QUALIFIER (ODBC 1.0) | 5 | Varchar | The identifier that is used to qualify the index name doing a DROP INDEX; NULL is returned if an index qualifier is not supported by the data source or if TYPE is SQL_TABLE_STAT. If a non-null value is returned in this column, it must be used to qualify the index name on a DROP INDEX statement; otherwise, the TABLE_SCHEM should be used to qualify the index name. |
| INDEX_NAME (ODBC 1.0) | 6 | Varchar | Index name; NULL is returned if TYPE is SQL_TABLE_STAT. |
| TYPE (ODBC 1.0) | 7 | Smallint not NULL | Type of information being returned: SQL_TABLE_STAT indicates a statistic for the table (in the CARDINALITY or PAGES column). SQL_INDEX_BTREE indicates a B-Tree index. SQL_INDEX_CLUSTERED indicates a clustered index. SQL_INDEX_CONTENT indicates a content index. SQL_INDEX_HASHED indicates a hashed index. SQL_INDEX_OTHER indicates another type of index. |
| ORDINAL_POSITION (ODBC 1.0) | 8 | Smallint | Column sequence number in index (starting with 1); NULL is returned if TYPE is SQL_TABLE_STAT. |
| COLUMN_NAME (ODBC 1.0) | 9 | Varchar | Column name. If the column is based on an expression, such as SALARY + BENEFITS, the expression is returned; if the expression cannot be determined, an empty string is returned. NULL is returned if TYPE is SQL_TABLE_STAT. |
| ASC_OR_DESC (ODBC 1.0) | 10 | Char(1) | Sort sequence for the column: "A" for ascending; "D" for descending; NULL is returned if column sort sequence is not supported by the data source or if TYPE is SQL_TABLE_STAT. |
| CARDINALITY (ODBC 1.0) | 11 | Integer | Cardinality of table or index; number of rows in table if TYPE is SQL_TABLE_STAT; number of unique values in the index if TYPE is not SQL_TABLE_STAT; NULL is returned if the value is not available from the data source. |
| PAGES (ODBC 1.0) | 12 | Integer | Number of pages used to store the index or table; number of pages for the table if TYPE is SQL_TABLE_STAT; number of pages for the index if TYPE is not SQL_TABLE_STAT; NULL is returned if the value is not available from the data source or if not applicable to the data source. |
| FILTER_CONDITION (ODBC 2.0) | 13 | Varchar | If the index is a filtered index, this is the filter condition, such as SALARY > 30000; if the filter condition cannot be determined, this is an empty string. NULL if the index is not a filtered index, it cannot be determined whether the index is a filtered index, or TYPE is SQL_TABLE_STAT. |
If the row in the result set corresponds to a table, the driver sets TYPE to SQL_TABLE_STAT and sets NON_UNIQUE, INDEX_QUALIFIER, INDEX_NAME, ORDINAL_POSITION, COLUMN_NAME, and ASC_OR_DESC to NULL. If CARDINALITY or PAGES are not available from the data source, the driver sets them to NULL.
Code Example
For a code example of a similar function, see SQLColumns.
Related Functions
| For information about | See |
|---|---|
| Binding a buffer to a column in a result set | SQLBindCol Function |
| Canceling statement processing | SQLCancel Function |
| Fetching a single row or a block of data in a forward-only direction. | SQLFetch Function |
| Fetching a block of data or scrolling through a result set | SQLFetchScroll Function |
| Returning the columns of foreign keys | SQLForeignKeys Function |
| Returning the columns of a primary key | SQLPrimaryKeys Function |