Tài liệu SQL Clearly Explained- P9 pptx

User-Dened Data Types and Typed Tables 413 Dereferencing for Data Access creates a table with a column that stores a reference to an in- gredient. e SCOPE clause species the table or view that is the source of the reference. To insert a row into a table with a REF column, you must include a SELECT in the INSERT statement that locates the row whose reference is to be stored. As you would expect, the object being referenced must exist in its own table before a reference to it can be generated. We must therefore rst insert an ingredient into the ingredient table: INSERT INTO ingredient VALUES (‘Unbleached flour,’ ‘cups’,25); en we can insert a referencing row into ingredient_amount: INSERT INTO ingredient_amount (SELECT REF (i) FROM ingredient i WHERE i.ingredient_name = ‘Unbleached flour’) VALUES (2.5); An application program that is using the recipe database as its data store will need to use the reference stored in the ingredi- ent_amount table to locate the name of the ingredient. e DEREF function follows a reference back to the table being referenced and returns data from the appropriate row. A query to retrieve the name and amount of an ingredient used in a recipe instruction could therefore be written: SELECT DEREF(related_ingredient).ingredient_name, amount FROM ingredient_amount WHERE DEREF(related_instruction).recipe_name = ‘French toast’; Note that the DEREF function accesses an entire row in the referenced table. If you don’t specify otherwise, you will re- trieve the values from every column in the referenced row. To Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 414 Chapter 19: Object-Relational Support retrieve just the value of a single column, we use “dot” nota- tion. e rst portion— DEREF(related_ingredient) —actually performs the dereference. e portion to the right of the dot species the column in the referenced row. Some DBMSs provide a dereference operator (->) that can be used in place of the DEREF function. e preceding query might be written: SELECT related_ingredient->ingredient_name, amount FROM ingredient_amount; e UDTs that we have seen to this point have attributes, but not methods. It is certainly possible, however, to declare meth- ods as part of a UDT and then to use SQL programming to dene the body of the methods. Like classes used by OO pro- gramming languages such C++, SQL the body a method is dened separately from the declaration of the UDT. You declare a method after declaring the structure of a UDT. For example, we could add a method to display the instruc- tions of a recipe with CREATE TYPE recipe_type AS OBJECT (recipe_name CHAR (256), instruction_list instruction ARRAY[20], numb_servings INT) NOT INSTANTIABLE, NOT FINAL METHOD show_instructions (); is particular method does not return a value and the dec- laration therefore does not include the optional RETURNS clause. However, a method to compute the cost of a recipe (if we were to include ingredient costs in the database) could be declared as Methods Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Methods 415 Dening Methods Executing Methods CREATE TYPE recipe_type AS OBJECT (recipe_name CHAR (256), instruction_list instruction ARRAY[20], numb_servings INT) NOT INSTANTIABLE, NOT FINAL METHOD show_instructions () METHOD compute_cost () RETURNS DECIMAL (5,2)); Methods can accept input parameters within the parentheses following the method name. A method declared as METHOD scale_recipe (IN numb_servings INT): accepts an integer value as an input value. e parameter list can also contain output parameters (OUT) and parameters used for both input and output (INOUT). As mentioned earlier, although methods are declared when UDTs tables are declared, the bodies of methods are written separately. To dene a method, use the CREATE METHOD statement: CREATE METHOD method_name FOR UDT_name BEGIN // body of method END A SQL-only method is written using the language constructs discussed in Chapter 14. Random programming note: Like the C++ and Java “this,” SQL methods use SELF to refer to the object to which the method belongs. Executing a method uses the “dot” notation used in C++: typed_table_name.method_name (parameter_list); Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 416 Chapter 19: Object-Relational Support Such an expression can be, for example, included in an IN- SERT statement to insert the method’s return value into a column. It can also be included in another SQL method, trig- ger, or stored procedure. Its return value can then be captured across an assignment operator. Output parameters return their values to the calling routine, where they can be used as needed. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Appendix A 419 Abbreviation/ Acronym Denition 1:1 One-to-one 1:M One-to-many ANSI American National Standards Institute API Application Program (or Programmer) Interface ASCII American Standard Code for Information Interchange CHAR Character CLI Command-line interface CTE Common table expression DBA Database administrator or Database administration DBMS Database management system DTD Document type denition ER Entity relationship ERD Entity relationship diagram FK or fk Foreign key GUI Graphic user interface HTML Hypertext markup language IE Information Engineering INT Integer Common Acronyms and Abbreviations Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 420 Appendix A: Common Acronyms and Abbreviations ISO International Standards Organization JDBC Java Database Connectivity M:M Many-to-many M:N Many-to-many NIST National Institute for Standards and Technology OO Object-oriented OODBMS Object-oriented database management system OOP Object-oriented programming OR Object-relational PK or pk Primary key PSM Persistent stored modules RDMBS Relational database management system SQL Structured query language UDF User-dened function UDT User-dened type; user-dened data type URI Uniform resource identier URL Uniform resource locator UML Unied modeling language VARCHAR Character varying XML Extended (Extensible) Markup Language Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. Appendix B 421 SQLSTATE Return Codes is appendix contains a numeric listing of the SQLSTATE re- turn codes specied in the SQL standard (Table B-1). SQLSTATE is a ve-character string. e leftmost two characters represent the error class; the rightmost three characters represent the subclass. Because SQLSTATE is a string, an embedded SQL program will need to use a substring function if it needs to separate the two parts of the code. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 422 Appendix B: SQLSTATE Return Codes Table B-1: SQLSTATE return codes Class Class denition Subclass Subclass denition 00 Successful completion 000 None 01 Warning 000 None 001 Cursor operation conict 002 Disconnect error 003 Null value eliminated in set function 004 String data, right truncation 005 Insucient item descriptor area 006 Privilege not revoked 007 Privilege not granted 008 Implicit zero-bit padding 009 Search expression too long for information schema 00A Query expression too long for information schema 00B Default value too long for information schema 00C Result sets returned 00D Additional result sets returned 00E Attempt to return too many result sets 00F Statement too long for information schema 010 Column cannot be mapped (XML) 011 SQL-Java path too long for information schema 02F Array data, right truncation 02 No data 000 None 001 No additional result sets returned 07 Dynamic SQL error 000 None 001 Using clause does not match dynamic parameter 002 Using clause does not match target specications Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 423 003 Cursor specication cannot be executed 004 Using clause required for dynamic parameters 005 Prepared statement not a cursor specication 006 Restricted data type attribute violation 007 Using clause required for result elds 008 Invalid descriptor count 009 Invalid descriptor index 00B Data type transform function violation 00C Undened DATA value 00D Invalid DATA target 00E invalid LEVEL value 00F Invalid DATETIME_INVERTVAL_CODE 08 Connection exception 000 None 001 SQL client unable to establish SQL connection 002 Connection name in use 003 Connection does not exist 004 SQL server rejected establishment of SQL connection 006 Connection failure 007 Transaction resolution unknown 09 Triggered action exception 000 None 0A Feature not supported 000 None 001 Multiple server transactions 0D Invalid target type specication 000 None 0E Invalid schema name list specication 000 None 0F Locator exception 000 None 001 Invalid specication 0K Resignal when handler not active 000 None 0L Invalid grantor 000 None Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 424 Appendix B: SQLSTATE Return Codes 0M Invalid SQL-invoked procedure reference 000 None 0N SQL/XML mapping error 000 None 001 Unmappable XML name 002 Invalid XML character 0P Invalid role specication 000 None 0S Invalid transform group name specication 000 None 0T Target table disagrees with cursor specication 000 None 0U Attempt to assign to non-updatable column 000 None 0V Attempt to assign to ordering column 000 None 0W Prohibited statement encountered during trigger execution 000 None 0X Invalid foreign server specication 000 None 0Y Pass-through specic condition 000 None 001 Invalid cursor option 002 Invalid cursor allocation 0Z Diagnostics exception 001 Maximum number of stacked diagnostics area exceeded 002 Stacked diagnostics accessed without active hander 10 XQuery error 000 None 20 Case not found for CASE statement 000 None 21 Cardinality violation 000 None 22 Data exception 000 None 001 String data, right truncation 002 Null value, no indicator 003 Numeric value out of range 004 Null value not allowed 005 Error in assignment 006 Invalid interval fomat 007 Invalid datetime format Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. [...]... embedded SQL: Embedded SQL in which the entire SQL statement cannot be assembled prior to running the program The SQL statement is therefore completed and processed during the program run Dynamic parameter: A value given to an embedded SQL statement at runtime rather than when the program in which the statement is contained is compiled Embedded SQL: SQL statements placed within a host language, allowing SQL. .. from a schema DROP VIEW view_name CASCADE | RESTRICT Execute an embedded SQL statement EXEC SQL complete _SQL_ statement Execute a prepared dynamic SQL statement EXECUTE [ GLOBAL | LOCAL ] prepared_dynamic _SQL_ statement [ INTO { parameter, … } | { SQL DESCRIPTOR [ GLOBAL | LOCAL ] descriptor_name } ] [ USING { parameter, … } | { SQL DESCRIPTOR [ GLOBAL | LOCAL ] descriptor_name } ] Please purchase PDF... exception 000 None 001 Request rejected 002 Request failed 37 Syntax error or access rule violation in dynamic SQL statement 000 None 38 External routine exception 000 None 001 Containing SQL not permitted 002 Modifying SQL not permitted 003 Prohibited SQL statement attempted 004 Reading SQL data not permitted 000 None 004 Null value not allowed 000 None 001 Invalid specification 002 Too many 39 3B... The second table (Table C.2) describes SQL built-in functions discussed in this book, including input data types In Table C.3 you will find SQL operators covered in the text Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 433 434  Appendix C: SQL Syntax Summary Table C.1: SQL statements Allocate space for a descriptor area for a dynamic SQL statement ALLOCATE DESCRIPTOR descriptor_name... 000 None 2A Syntax error or access rule violation in direct SQL statement 000 None 2B Dependent privilege descriptors still exist 000 None 2C Invalid character set name 000 None 2D Invalid transaction termination 000 None 2E Invalid connection name 000 None 2F SQL routine exception 000 None 002 Modifying SQL data not permitted 003 Prohibited SQL statement attempted Please purchase PDF Split-Merge on... prepared_dynamic _SQL_ statement_name Delete rows from a table DELETE FROM table_name [ { WHERE row_selection_predicate } | { WHERE CURRENT OF cursor_name } ] Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark   437 Describe the dynamic parameters in a prepared dynamic SQL statement for a descriptor area DESCRIBE [ INPUT | OUTPUT ] Prepared_dyamic _SQL_ statement_name USING SQL DESCRIPTOR... attempted Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark 428  Appendix B: SQLSTATE Return Codes 004 Reading SQL data not permitted 005 Function executed but no return statement 2H Invalid collation name 000 None 30 Invalid SQL statement identifier 000 None 33 Invalid SQL descriptor name 000 None 34 Invalid cursor name 000 None 35 Invalid condition number 000 None 36 Cursor... 438  Appendix C: SQL Syntax Summary Execute a dynamic SQL statement immediately, without a separate preparation step EXECUTE IMMEDIATE SQL_ statement_text_literal_or_variable Retrieve a row from an open cursor’s result table FETCH [ NEXT | PRIOR | FIRST | LAST | ABSOLUTE | { RELATIVE row_number } ] FROM cursor_name INTO host_language_variable, … Retrieve information from a dynamic SQL descriptor area... executing the SELECT and positioning the cursor at the first row OPEN cursor_name [ { USING host_language_variable_or_literal, … } | { SQL DESCRIPTOR descriptor_name } ] Prepare a dynamic SQL statement for execution PREPARE [ GLOBAL | LOCAL ] prepared_dynamic _SQL_ statement_name FROM SQL_ statement_text_literal_or_variable Remove access rights from a user REMOVE [GRANT OPTION FOR ] { ALL PRIVILEGES } | SELECT... state 000 None 001 Active SQL transaction 002 Branch transaction already active 003 Inappropriate access mode for branch transaction 004 Inappropriate isolation level for branch transaction 005 No active SQL transaction for branch transaction 006 Read-only SQL transaction 007 Schema and data statement mixing not supported 008 Held cursor requires same isolation level 26 Invalid SQL statement name 000 . watermark. Appendix B 421 SQLSTATE Return Codes is appendix contains a numeric listing of the SQLSTATE re- turn codes specied in the SQL standard (Table B-1). SQLSTATE. None 001 SQL client unable to establish SQL connection 002 Connection name in use 003 Connection does not exist 004 SQL server rejected establishment of SQL