DOCUMENT:Q196084 27-JUL-2001 [foxpro] TITLE :HOWTO: Retrieve Foreign Key Information from SQL Server PRODUCT :Microsoft FoxPro PROD/VER:MACINTOSH:3.0b; WINDOWS:2.5,3.0,3.0b,5.0,5.0a,6.0 OPER/SYS: KEYWORDS:kbClient KbClientServer kbDatabase kbSQL kbvfp kbvfp300b kbvfp500 kbvfp500a kbvfp600 kb ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0 - Microsoft Visual FoxPro for Macintosh, version 3.0b - Microsoft Data Access Components version 2.5 ------------------------------------------------------------------------------- SUMMARY ======= When creating remote views using SQL Server tables as the data source, Visual FoxPro automatically sets the KeyField property to .T. for columns that are included in a primary index key. You can use the SQL Server stored procedure, sp_pkeys, to return primary key information from SQL Server. The sp_pkeys stored procedure, however, does not return information regarding the relationship(s) between tables. In some circumstances, a developer may want to retrieve the foreign key information programmatically to provide greater detail of the relationship between tables. This article shows how to use the stored procedure sp_fkeys to return foreign key information from SQL Server. MORE INFORMATION ================ The sp_fkeys stored procedure returns a cursor with logical foreign key information for the current environment. This procedure shows foreign key relationships including disabled foreign keys. The sp_fkeys stored procedure is equivalent to SQLForeignKeys in ODBC. The results returned are ordered by FKTABLE_QUALIFIER, FKTABLE_OWNER, FKTABLE_NAME, and KEY_SEQ. The columns returned by sp_fkeys follow: Column Name Description ----------------------------------------------------------------------- PKTABLE_QUALIFIER Name of the table (with the primary key) qualifier. This column represents the database name for the table with a PRIMARY KEY constraint and may be NULL. PKTABLE_OWNER Name of the table (with the primary key) owner. This column represents the name of the database user that created the table (with a PRIMARY KEY constraint) and always returns a value. PKTABLE_NAME Name of the table (with the primary key). This column represents the table name (with a PRIMARY KEY constraint) as listed in the sysobjects table and always returns a value. PKCOLUMN_NAME Name of the primary key column(s), for each column of the TABLE_NAME returned. This column represents the column name as listed in the syscolumns table and always returns a value. FKTABLE_QUALIFIER Name of the table (with a foreign key) qualifier. This column represents the database name for the table (with a FOREIGN KEY constraint) and may be NULL. FKTABLE_OWNER Name of the table (with a foreign key) owner. This column represents the name of the database user that created the table (with a FOREIGN KEY constraint) and always returns a value. FKTABLE_NAME Name of the table (with a foreign key). This column represents the table name as listed in the sysobjects table (with a FOREIGN KEY constraint) and always returns a value. FKCOLUMN_NAME Name of the foreign key column(s), for each column of the TABLE_NAME returned. This column represents the column name as listed in the syscolumns table and always returns a value. KEY_SEQ Sequence number of the column in a multicolumn primary key. This field always returns a value. UPDATE_RULE Action applied to the foreign key when the SQL operation is UPDATE. SQL Server returns 1 for this column. DELETE_RULE Action applied to the foreign key when the SQL operation is DELETE. SQL Server returns 1 for this column. FK_NAME Foreign key identifier. This is the FOREIGN KEY constraint name, and may be NULL if not applicable to the data source. PK_NAME Primary key identifier. This is the PRIMARY KEY constraint name, and may be NULL if not applicable to the data source. Create a program named SP_fkeys.prg using the following code: * Substitute the server name. #DEFINE Connect_String 'DRIVER={SQL Server};SERVER=MY_SERVER;' + ; 'DATABASE=PUBS;UID=sa;PWD=' * Create a cursor to store information. CREATE CURSOR SQLKeys (Parent_Qualifier c(128), Parent_Owner c(128), ; Parent_Table_Name c(128), Parent_Column_Name c(128), ; Foreign_Qualifier c(128), Foreign_Owner c(128), ; Foreign_Table_Name c(128), Foreign_Column_Name c(128), ; Key_Seq I, FK_NAME c(128), PK_Name c(128)) * Connect to SQL Server. gnConnHandle=SQLSTRINGCONN(Connect_String) IF gnConnHandle>0 * Get the tables available on SQL Server. SQLConnTables=SQLTABLES(gnConnHandle) IF SQLConnTables>0 SELECT SQLResult INCnt=0 DO WHILE !EOF() * Create a command to execute the stored procedure. SQLCommand="sp_fkeys " + ALLTRIM(Table_Name) * Execute the stored procedure and return data to a cursor. =SQLEXEC(gnConnHandle,SQLCommand,'syskeys') * Select the cursor. SELECT SYSKeys IF RECCOUNT()>0 SELECT SQLKeys SQLKEY_Exists=.F. SCAN FOR Parent_Table_Name=SYSKeys.PKTable_Name ; AND Foreign_Table_Name=SYSKeys.FKTable_Name * Multicolumn key. * Concatenate to get the expression. REPLACE SQLKeys.Foreign_Column_Name WITH ; ALLTRIM(SQLKeys.Foreign_Column_Name) + ; "+" + ALLTRIM(SYSKeys.FKColumn_Name) SQLKEY_Exists=.T. ENDSCAN IF !SQLKEY_Exists * Insert a new record into the SQLKeys cursor. INSERT INTO SQLKeys ; VALUES ; (SYSKeys.PKTable_Qualifier, SYSKeys.PKTable_Owner, ; SYSKeys.PKTable_Name, SYSKeys.PKColumn_Name, ; SYSKeys.FKTable_Qualifier, SYSKeys.FKTable_Owner, ; SYSKeys.FKTable_Name,SYSKeys.FKColumn_Name, ; SYSKeys.Key_Seq,SYSKeys.FK_NAME,SYSKeys.PK_Name) ENDIF ENDIF SELECT SQLResult SKIP ENDDO =SQLDISCONN(gnConnHandle) ENDIF ENDIF SELECT SQLKeys BROW LAST CLOSE ALL RETURN In the Command window enter and run the following code: DO SP_FKEYS REFERENCES ========== Transact - SQL Help; search on: "sp_fkeys" (c) Microsoft Corporation 1998, All Rights Reserved. Contributions by John Desch, Microsoft Corporation. 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