Read Write BLOBs from to SQL Server using C. NET Data. Reader. Obtaining BLOB Values from a Database. The default behavior of the Data. Reader is to. load incoming data as a row as soon as an entire row of data is available. Binary large. objects BLOBs need to be treated differently, however, because they can contain. The. Command. Execute. Sql Write Binary Data To File' title='Sql Write Binary Data To File' />Reader method has an overload which will take a. Command. Behavior argument to modify the default behavior of the Data. Reader. You can. pass Command. Behavior. Sequential. Sql Write Binary Data To File' title='Sql Write Binary Data To File' />Read Write BLOBs from to SQL Server using C. NET DataReader. More Information on installing the. Net Framework click here. Download full Visual Studio C. NET. Data files should not be put on compressed file systems unless the files are readonly secondary files, or if the database is readonly. Log files should never be put. C language interview questions solution for freshers beginners placement tricky good pointers answers explanation operators data types arrays structures functions. ZnJvbT1jc2RuJnVybD1RM2NoVkVhMFYzYlQ5U2UwbG1kaEozWnZBek52VW1kczkyY3psR1p2MFRQQjEwUUd0V1VDcEVNSjlDYnNsbVp2QURNMDhTWjZsMmMwNTJibTlDVnl3VU5NWlRZMThDZHU5bVp2MFRQbkpHYVc1V1kyWjBSaFpqUlhKbWRSaGxXMVZUYWl0bVR6a1ZkakpqWXpwa01NWjNiRU5HTVNoVVl2UUhlbFIzTHk4eWF5RldieVZHZGhkM1AyVVRNeFFqTXpZVE13TVROd1FUTXdJekwwVm1idTRHWnpObUxuOUdiaTV5WnRsMkx2b0RjMFJIYQ.jpg' alt='Sql Write Binary Data To File' title='Sql Write Binary Data To File' />12 Tuning PLSQL Applications for Performance. This chapter explains how to write efficient new PLSQL code and speed up existing PLSQL code. Topics. SQL Server articles, scripts, and discussion groups. Sql Write Binary Data To File' title='Sql Write Binary Data To File' />Access to the Execute. Reader method to modify the. Data. Reader so that instead of loading rows of data, it will load. This is ideal for loading BLOBs or other large data. Note that this behavior may differ depending on your data source. Provides a way for the Data. Reader to handle rows. BLOBs. Rather than loading the entire row, Sequential. Access. enables the Data. Reader to load data as a stream. When setting the Data. Reader to. use Sequential. Access, it is important to note the sequence in which you access the. The default behavior of the Data. Reader, which loads an entire row as. When using Sequential. Access however, you must access the different. Data. Reader in order. For example, if your query returns three. BLOB, you must return the values of the first and second. BLOB data in the third field. If you access the third field. This is because Sequential. Access has modified the Data. Reader to return data in. Data. Reader has read past. When accessing the data in the BLOB field, use. Get. Bytes or Get. Chars typed accessors of the Data. Reader, which fill an. You can also use Get. String for character data, however to conserve. BLOB value into a single string. You can specify a specific buffer size of data to be returned, and a starting. Get. Bytes and. Get. Chars will return a long value, which represents the number of bytes or characters. If you pass a null array to Get. Bytes or Get. Chars, the long value returned. BLOB. You can optionally specify. Writing BLOB Values to a Database. You can write a binary large object BLOB to a. To write a BLOB value to your database, issue the appropriate INSERT or UPDATE. BLOB value as an input parameter. If your BLOB is stored as text. SQL Server text field, you can pass the BLOB as a string parameter. If the. BLOB is stored in binary format, such as a SQL Server image field, you can pass an array. Example. The following code example adds employee information to the Employees table in. Northwind database. A photo of the employee is read from a file and added to. Photo field in the table, which is an image field. The Photo field is then read using Get. Bytes. Notice that the employee id. Photo, because the fields must be. System using System. Drawing using System. Collections using System. Component. Model using System. Windows. Forms using System. Data using System. Data. Sql. Client using System. IO namespace Akadia. Read. Write. Blob Read and Write BLOB tofrom Filesystem and. Databasepublic class Blob. Sample System. Windows. Forms. Formprivate System. Windows. Forms. Picture. Box. pbx. Photo private System. Component. Model. Container. components null private System. Windows. Forms. Button. Load. Photo private System. Windows. Forms. Button. Add. Emp private System. Windows. Forms. Button. Get. Emp private System. Windows. Forms. Status. Bar. status. Bar        My own private. Variablesprivate String fname null private Sql. Connection conn        Constructorpublic Blob. Sample. Initialize GUIInitialize. Component           . Get Database Connectionconn new. Sql. Connectiondata sourceXEON initial catalogNorthwind user idsa passwordmanager         Read Image from. Filesystem and add it to the Database. Add. Employeestring plast. Name,string pfirst. Name,string ptitle,Date. Time phire. Date,int preports. To,string. photo. File. Path           . Read Image into Byte Array from Filesystembyte photo. Get. Photophoto. File. Path           . Construct INSERT Command. Sql. Command add. Emp new. Sql. CommandINSERT INTO Employees Last. Name,First. Name,Title,Hire. Date,Reports. To,Photo VALUESLast. Name,First. Name,Title,Hire. Date,Reports. To,Photo,conn. Emp. Parameters. AddLast. Name,  Sql. Db. Type. NVar. Char, 2. 0. Value plast. Name add. Emp. Parameters. AddFirst. Name, Sql. Db. Type. NVar. Char, 1. 0. Value pfirst. Name add. Emp. Parameters. AddTitle,     Sql. Db. Type. NVar. Char, 3. Value. ptitle add. Emp. Parameters. AddHire. Date,  Sql. Db. Type. Date. Time. Value. Date add. Emp. Parameters. AddReports. To. Sql. Db. Type. Int. Value         . To add. Emp. Parameters. AddPhoto,     Sql. Db. Type. Image. photo. Length. Value photo           . Open the Connection and INSERT the BLOB into the Databaseconn. Open add. Emp. Execute. Non. Query conn. Close         Read Image into. Byte Array from Filesystempublic static byte Get. Photostring. file. PathFile. Stream fs new. File. Streamfile. Path, File. Mode. Open, File. Access. Read Binary. Reader br new. Binary. Readerfs            byte photo. Read. Bytesintfs. Length            br. Close fs. Close            return photo         Read BLOB from. Database and save it on the Filesystempublic void Get. Employeestring. plast. Name,string pfirst. NameSql. Command get. Emp new. Sql. CommandSELECT Employee. ID, Photo FROM Employees WHERE Last. Name last. Name AND First. Name first. Name, conn. Emp. Parameters. AddLast. Sears Roebuck Shotgun Serial Numbers here. Name,  Sql. Db. Type. NVar. Char, 2. 0. Value plast. Name get. Emp. Parameters. AddFirst. Name, Sql. Db. Type. NVar. Char, 1. 0. Value pfirst. Name            File. Stream. fs. Writes the BLOB to a file Binary. Writer. bw. Streams the BLOB to the File. Stream object. int buffer. Size. 1. 00. Size of the BLOB buffer. Size  The BLOB byte buffer to be filled by. Get. Bytes. long. The bytes returned from Get. Bytes. long start. Index. 0. The starting position in the BLOB output. The employee id to use in the file name. Open the connection and read data into the Data. Reader. conn. Open Sql. Data. Reader my. Reader. Emp. Execute. ReaderCommand. Behavior. Sequential. Access            while. Reader. Read Get the employee id, which must occur before getting the. Reader. Get. Int. To. String. Create a file to hold the output. File. Streamemployee empid. File. Mode. Open. Or. Create, File. Access. Write bw new Binary. Writerfs. Reset the starting byte for the new BLOB. Index 0. Read the bytes into outbyte and retain the number of bytes. Reader. Get. Bytes1, start. Index, outbyte, 0, buffer. Size. Continue reading and writing while there are bytes beyond the size. Sizebw. Writeoutbyte bw. Flush. Reposition the start index to the end of the last buffer and fill. Index buffer. Size retval my. Reader. Get. Bytes1, start. Index, outbyte, 0, buffer. Size. Write the remaining buffer. Writeoutbyte, 0, intretval bw. Flush. Close the output file. Close fs. Close            . Close the reader and the connection. Reader. Close conn. Close         private void btn. Add. EmpClickobject sender. System. Event. Args eDate. Time hire. Date. Date. Time. Parse2. Add. EmployeeMary,Jones,Software Engineer,hire. Date,5,fname status. Bar. Text. Employee added to the Database         private void btn. Get. EmpClickobject sender. System. Event. Args eGet. Tuning PLSQL Applications for Performance. PLSQL sends SQL statements such as DML and queries to the SQL engine for execution, and SQL returns the results to PLSQL. You can minimize the performance overhead of this communication between PLSQL and SQL by using the PLSQL features that are known collectively as bulk SQL. The FORALL statement sends INSERT, UPDATE, or DELETE statements in batches, rather than one at a time. The BULKCOLLECT clause brings back batches of results from SQL. If the DML statement affects four or more database rows, bulk SQL can improve performance considerably. Assigning values to PLSQL variables in SQL statements is called binding. PLSQL binding operations fall into these categories Bulk SQL uses PLSQL collections to pass large amounts of data back and forth in single operations. This process is called bulk binding. If the collection has n elements, bulk binding uses a single operation to perform the equivalent of n. SELECTINTO, INSERT, UPDATE, or DELETE statements. A query that uses bulk binding can return any number of rows, without requiring a FETCH statement for each one. To speed up INSERT, UPDATE, and DELETE statements, enclose the SQL statement within a PLSQL FORALL statement instead of a LOOP statement. To speed up SELECTINTO statements, include the BULKCOLLECT clause. Running One DML Statement Multiple Times FORALL StatementThe keyword FORALL lets you run multiple DML statements very efficiently. It can only repeat a single DML statement, unlike a general purpose FOR loop. For full syntax and restrictions, see FORALL Statement. The SQL statement can reference more than one collection, but FORALL only improves performance where the index value is used as a subscript. Usually, the bounds specify a range of consecutive index numbers. If the index numbers are not consecutive, such as after you delete collection elements, you can use the INDICESOF or VALUESOF clause to iterate over just those index values that really exist. The INDICESOF clause iterates over all of the index values in the specified collection, or only those between a lower and upper bound. The VALUESOF clause refers to a collection that is indexed by PLSINTEGER and whose elements are of type PLSINTEGER. The FORALL statement iterates over the index values specified by the elements of this collection. The FORALL statement in Example 1. DELETE statements to the SQL engine at once. Example 1. 2 2 Issuing DELETE Statements in a Loop. CREATE TABLE employeestemp AS SELECT FROM employees. TYPE Num. List IS VARRAY2. OF NUMBER. depts Num. List Num. List1. FORALL i IN depts. FIRST. depts. LAST. DELETE FROM employeestemp WHERE departmentid deptsi. Example 1. 2 3 loads some data into PLSQL collections. Then it inserts the collection elements into a database table twice first using a FOR loop, then using a FORALL statement. The FORALL version is much faster. Example 1. 2 3 Issuing INSERT Statements in a Loop. CREATE TABLE parts. INTEGER, pname VARCHAR21. CREATE TABLE parts. INTEGER, pname VARCHAR21. TYPE Num. Tab IS TABLE OF parts. TYPE INDEX BY PLSINTEGER. TYPE Name. Tab IS TABLE OF parts. TYPE INDEX BY PLSINTEGER. Num. Tab. pnames Name. Tab. iterations CONSTANT PLSINTEGER 5. FOR j IN 1. iterations LOOP load index by tables. Part No. TOCHARj. DBMSUTILITY. gettime. FOR i IN 1. iterations LOOP use FOR loop. INSERT INTO parts. VALUES pnumsi, pnamesi. DBMSUTILITY. gettime. FORALL i IN 1. iterations use FORALL statement. INSERT INTO parts. VALUES pnumsi, pnamesi. DBMSUTILITY. gettime. DBMSOUTPUT. PUTLINEExecution Time secs. DBMSOUTPUT. PUTLINE . DBMSOUTPUT. PUTLINEFOR loop TOCHARt. DBMSOUTPUT. PUTLINEFORALL TOCHARt. Executing this block shows that the loop using FORALL is much faster. The bounds of the FORALL loop can apply to part of a collection, not necessarily all the elements, as shown in Example 1. Example 1. 2 4 Using FORALL with Part of a Collection. CREATE TABLE employeestemp AS SELECT FROM employees. TYPE Num. List IS VARRAY1. OF NUMBER. depts Num. List Num. List5,1. FORALL j IN 4. 7 use only part of varray. DELETE FROM employeestemp WHERE departmentid deptsj. You might need to delete some elements from a collection before using the collection in a FORALL statement. The INDICESOF clause processes sparse collections by iterating through only the remaining elements. You might also want to leave the original collection alone, but process only some elements, process the elements in a different order, or process some elements more than once. Instead of copying the entire elements into new collections, which might use up substantial amounts of memory, the VALUESOF clause lets you set up simple collections whose elements serve as pointers to elements in the original collection. Example 1. 2 5 creates a collection holding some arbitrary data, a set of table names. Deleting some of the elements makes it a sparse collection that does not work in a default FORALL statement. The program uses a FORALL statement with the INDICESOF clause to insert the data into a table. It then sets up two more collections, pointing to certain elements from the original collection. The program stores each set of names in a different database table using FORALL statements with the VALUESOF clause. Example 1. 2 5 Using FORALL with Nonconsecutive Index Values. Create empty tables to hold order details. CREATE TABLE validorders custname VARCHAR23. NUMBER1. 0,2. CREATE TABLE bigorders AS SELECT FROM validorders. WHERE 1 0. CREATE TABLE rejectedorders AS SELECT FROM validorders. Collections for set of customer names order amounts. SUBTYPE custname IS validorders. TYPE. TYPE custtyp IS TABLe OF custname. SUBTYPE orderamount IS validorders. TYPE. TYPE amounttyp IS TABLE OF NUMBER. Collections to point into CUSTTAB collection. TYPE indexpointert IS TABLE OF PLSINTEGER. PROCEDURE setupdata IS BEGIN. Set up sample order data. Company. 1,Company. Company. 3,Company. Company. 5. amounttab amounttyp5. NULL. setupdata. DBMSOUTPUT. PUTLINE. Original order data. FOR i IN 1. custtab. LAST LOOP. DBMSOUTPUT. PUTLINE. Customer i, custtabi . Delete invalid orders where amount is null or 0. FOR i IN 1. custtab. LAST LOOP. IF amounttabi is null or amounttabi 0 THEN. DBMSOUTPUT. PUTLINE. Data with invalid orders deleted. FOR i IN 1. custtab. LAST LOOP. IF custtab. EXISTSi THEN. DBMSOUTPUT. PUTLINECustomer i,. Veeam Fastscp 64 Bit. Because subscripts of collections are not consecutive. FORALL. INDICES OF to iterate through actual subscripts. COUNT. FORALL i IN INDICES OF custtab. INSERT INTO validorderscustname, amount. VALUEScusttabi, amounttabi. Now process the order data differently. Extract 2 subsets and store each subset in a different table. Initialize the CUSTTAB and AMOUNTTAB collections again. FOR i IN custtab. FIRST. custtab. LAST LOOP. IF amounttabi IS NULL OR amounttabi 0 THEN. Add a new element to this collection. EXTEND. Record the subscript from the original collection. Windows 95 Iso Ita Torrent more. LAST i. IF amounttabi 2. THEN. Add a new element to this collection. EXTEND. Record the subscript from the original collection. LAST i. Now its easy to run one DML statement. DML statement on a different subset. FORALL i IN VALUES OF rejectedordertab. INSERT INTO rejectedorders. VALUES custtabi, amounttabi.