BULK INSERT (Transact-SQL)

Artykuł
02/13/2015

Imports a data file into a database table or view in a user-specified format.

Ikona łącza do tematu Transact-SQL Syntax Conventions

Składnia

BULK INSERT 
   [ database_name . [ schema_name ] . | schema_name . ] [ table_name | view_name ] 
      FROM 'data_file' 
     [ WITH 
    ( 
   [ [ , ] BATCHSIZE = batch_size ] 
   [ [ , ] CHECK_CONSTRAINTS ] 
   [ [ , ] CODEPAGE = { 'ACP' | 'OEM' | 'RAW' | 'code_page' } ] 
   [ [ , ] DATAFILETYPE = 
      { 'char' | 'native'| 'widechar' | 'widenative' } ] 
   [ [ , ] FIELDTERMINATOR = 'field_terminator' ] 
   [ [ , ] FIRSTROW = first_row ] 
   [ [ , ] FIRE_TRIGGERS ] 
   [ [ , ] FORMATFILE = 'format_file_path' ] 
   [ [ , ] KEEPIDENTITY ] 
   [ [ , ] KEEPNULLS ] 
   [ [ , ] KILOBYTES_PER_BATCH = kilobytes_per_batch ] 
   [ [ , ] LASTROW = last_row ] 
   [ [ , ] MAXERRORS = max_errors ] 
   [ [ , ] ORDER ( { column [ ASC | DESC ] } [ ,...n ] ) ] 
   [ [ , ] ROWS_PER_BATCH = rows_per_batch ] 
   [ [ , ] ROWTERMINATOR = 'row_terminator' ] 
   [ [ , ] TABLOCK ] 
   [ [ , ] ERRORFILE = 'file_name' ] 
    )]

Arguments

database_name
Is the database name in which the specified table or view resides. If not specified, this is the current database.
schema_name
Is the name of the table or view schema. schema_name is optional if the default schema for the user performing the bulk-import operation is schema of the specified table or view. If schema is not specified and the default schema of the user performing the bulk-import operation is different from the specified table or view, SQL Server returns an error message, and the bulk-import operation is canceled.
table_name
Is the name of the table or view to bulk import data into. Only views in which all columns refer to the same base table can be used. For more information about the restrictions for loading data into views, see INSERT (Transact-SQL).
' data_file '
Is the full path of the data file that contains data to import into the specified table or view. BULK INSERT can import data from a disk (including network, floppy disk, hard disk, and so on).

data_file must specify a valid path from the server on which SQL Server is running. If data_file is a remote file, specify the Universal Naming Convention (UNC) name. A UNC name has the form \\Systemname\ShareName\Path\FileName. For example, \\SystemX\DiskZ\Sales\update.txt.
BATCHSIZE **=**batch_size
Specifies the number of rows in a batch. Each batch is copied to the server as one transaction. If this fails, SQL Server commits or rolls back the transaction for every batch. By default, all data in the specified data file is one batch. For information about performance considerations, see "Remarks," later in this topic.
CHECK_CONSTRAINTS
Specifies that all constraints on the target table or view must be checked during the bulk-import operation. Without the CHECK_CONSTRAINTS option, any CHECK and FOREIGN KEY constraints are ignored, and after the operation, the constraint on the table is marked as not-trusted.

[!UWAGA]

UNIQUE and PRIMARY KEY constraints are always enforced. When importing into a character column that is defined with a NOT NULL constraint, BULK INSERT inserts a blank string when there is no value in the text file.

At some point, you must examine the constraints on the whole table. If the table was non-empty before the bulk-import operation, the cost of revalidating the constraint may exceed the cost of applying CHECK constraints to the incremental data.

A situation in which you might want constraints disabled (the default behavior) is if the input data contains rows that violate constraints. With CHECK constraints disabled, you can import the data and then use Transact-SQL statements to remove the invalid data.

[!UWAGA]

The MAXERRORS option does not apply to constraint checking.

[!UWAGA]

In SQL Server 2005 and later versions, BULK INSERT enforces new data validation and data checks that could cause existing scripts to fail when they are executed on invalid data in a data file.

CODEPAGE = { 'ACP' | 'OEM' | 'RAW' | 'code_page' }
Specifies the code page of the data in the data file. CODEPAGE is relevant only if the data contains char, varchar, or text columns with character values greater than 127 or less than 32.

[!UWAGA]

Microsoft recommends that you specify a collation name for each column in a format file.

ACP

Columns of char, varchar, or text data type are converted from the ANSI/Microsoft Windows code page (ISO 1252) to the SQL Server code page.

OEM (default)

Columns of char, varchar, or text data type are converted from the system OEM code page to the SQL Server code page.

RAW

No conversion from one code page to another occurs; this is the fastest option.

code_page

Specific code page number, for example, 850.

Ważne:
SQL Server does not support code page 65001 (UTF-8 encoding).

DATAFILETYPE = { 'char' | 'native' | 'widechar' | 'widenative' }
Specifies that BULK INSERT performs the import operation using the specified data-file type value.

DATAFILETYPE value	All data represented in:
char (default)	Character format. For more information, see Use Character Format to Import or Export Data (SQL Server).
native	Native (database) data types. Create the native data file by bulk importing data from SQL Server using the bcp utility. The native value offers a higher performance alternative to the char value. For more information, see Use Native Format to Import or Export Data (SQL Server).
widechar	Unicode characters. For more information, see Use Unicode Character Format to Import or Export Data (SQL Server).
widenative	Native (database) data types, except in char, varchar, and text columns, in which data is stored as Unicode. Create the widenative data file by bulk importing data from SQL Server using the bcp utility. The widenative value offers a higher performance alternative to widechar. If the data file contains ANSI extended characters, specify widenative. For more information, see Use Unicode Native Format to Import or Export Data (SQL Server).

FIELDTERMINATOR ='field_terminator'
Specifies the field terminator to be used for char and widechar data files. The default field terminator is \t (tab character). For more information, see Specify Field and Row Terminators (SQL Server).
FIRSTROW **=**first_row
Specifies the number of the first row to load. The default is the first row in the specified data file. FIRSTROW is 1-based.

[!UWAGA]

The FIRSTROW attribute is not intended to skip column headers. Skipping headers is not supported by the BULK INSERT statement. When skipping rows, the SQL Server Database Engine looks only at the field terminators, and does not validate the data in the fields of skipped rows.
FIRE_TRIGGERS
Specifies that any insert triggers defined on the destination table execute during the bulk-import operation. If triggers are defined for INSERT operations on the target table, they are fired for every completed batch.

If FIRE_TRIGGERS is not specified, no insert triggers execute.
FORMATFILE ='format_file_path'
Specifies the full path of a format file. A format file describes the data file that contains stored responses created by using the bcp utility on the same table or view. The format file should be used if:
- The data file contains greater or fewer columns than the table or view.
- The columns are in a different order.
- The column delimiters vary.
- There are other changes in the data format. Format files are typically created by using the bcp utility and modified with a text editor as needed. For more information, see bcp Utility.
KEEPIDENTITY
Specifies that identity value or values in the imported data file are to be used for the identity column. If KEEPIDENTITY is not specified, the identity values for this column are verified but not imported and SQL Server automatically assigns unique values based on the seed and increment values specified during table creation. If the data file does not contain values for the identity column in the table or view, use a format file to specify that the identity column in the table or view is to be skipped when importing data; SQL Server automatically assigns unique values for the column. For more information, see DBCC CHECKIDENT (Transact-SQL).

For more information, see about keeping identify values see Keep Identity Values When Bulk Importing Data (SQL Server).
KEEPNULLS
Specifies that empty columns should retain a null value during the bulk-import operation, instead of having any default values for the columns inserted. For more information, see Keep Nulls or Use Default Values During Bulk Import (SQL Server).
KILOBYTES_PER_BATCH = kilobytes_per_batch
Specifies the approximate number of kilobytes (KB) of data per batch as kilobytes_per_batch. By default, KILOBYTES_PER_BATCH is unknown. For information about performance considerations, see "Remarks," later in this topic.
LASTROW**=**last_row
Specifies the number of the last row to load. The default is 0, which indicates the last row in the specified data file.
MAXERRORS = max_errors
Specifies the maximum number of syntax errors allowed in the data before the bulk-import operation is canceled. Each row that cannot be imported by the bulk-import operation is ignored and counted as one error. If max_errors is not specified, the default is 10.

[!UWAGA]

The MAX_ERRORS option does not apply to constraint checks or to converting money and bigint data types.
ORDER ( { column [ ASC | DESC ] } [ ,... n ] )
Specifies how the data in the data file is sorted. Bulk import performance is improved if the data being imported is sorted according to the clustered index on the table, if any. If the data file is sorted in a different order, that is other than the order of a clustered index key or if there is no clustered index on the table, the ORDER clause is ignored. The column names supplied must be valid column names in the destination table. By default, the bulk insert operation assumes the data file is unordered. For optimized bulk import, SQL Server also validates that the imported data is sorted.
n
Is a placeholder that indicates that multiple columns can be specified.
ROWS_PER_BATCH **=**rows_per_batch
Indicates the approximate number of rows of data in the data file.

By default, all the data in the data file is sent to the server as a single transaction, and the number of rows in the batch is unknown to the query optimizer. If you specify ROWS_PER_BATCH (with a value > 0) the server uses this value to optimize the bulk-import operation. The value specified for ROWS_PER_BATCH should approximately the same as the actual number of rows. For information about performance considerations, see "Remarks," later in this topic.
ROWTERMINATOR ='row_terminator'
Specifies the row terminator to be used for char and widechar data files. The default row terminator is \r\n (newline character). For more information, see Specify Field and Row Terminators (SQL Server).
TABLOCK
Specifies that a table-level lock is acquired for the duration of the bulk-import operation. A table can be loaded concurrently by multiple clients if the table has no indexes and TABLOCK is specified. By default, locking behavior is determined by the table option table lock on bulk load. Holding a lock for the duration of the bulk-import operation reduces lock contention on the table, in some cases can significantly improve performance. For information about performance considerations, see "Remarks," later in this topic.
ERRORFILE ='file_name'
Specifies the file used to collect rows that have formatting errors and cannot be converted to an OLE DB rowset. These rows are copied into this error file from the data file "as is."

The error file is created when the command is executed. An error occurs if the file already exists. Additionally, a control file that has the extension .ERROR.txt is created. This references each row in the error file and provides error diagnostics. As soon as the errors have been corrected, the data can be loaded.

Compatibility

BULK INSERT enforces strict data validation and data checks of data read from a file that could cause existing scripts to fail when they are executed on invalid data. For example, BULK INSERT verifies that:

The native representations of float or real data types are valid.
Unicode data has an even-byte length.

Data Types

String-to-Decimal Data Type Conversions

The string-to-decimal data type conversions used in BULK INSERT follow the same rules as the Transact-SQL CONVERT function, which rejects strings representing numeric values that use scientific notation. Therefore, BULK INSERT treats such strings as invalid values and reports conversion errors.

To work around this behavior, use a format file to bulk import scientific notation float data into a decimal column. In the format file, explicitly describe the column as real or float data. For more information about these data types, see float and real (Transact-SQL).

[!UWAGA]

Format files represent real data as the SQLFLT4 data type and float data as the SQLFLT8 data type. For information about non-XML format files, see Specify File Storage Type by Using bcp (SQL Server).

Example of Importing a Numeric Value that Uses Scientific Notation

This example uses the following table:

CREATE TABLE t_float(c1 float, c2 decimal (5,4))

The user wants to bulk import data into the t_float table. The data file, C:\t_float-c.dat, contains scientific notation float data; for example:

8.0000000000000002E-28.0000000000000002E-2

However, BULK INSERT cannot import this data directly into t_float, because its second column, c2, uses the decimal data type. Therefore, a format file is necessary. The format file must map the scientific notation float data to the decimal format of column c2.

The following format file uses the SQLFLT8 data type to map the second data field to the second column:

<?xml version="1.0"?>

To use this format file (using the file name C:\t_floatformat-c-xml.xml) to import the test data into the test table, issue the following Transact-SQL statement:

BULK INSERT bulktest..t_float
FROM 'C:\t_float-c.dat' WITH (FORMATFILE='C:\t_floatformat-c-xml.xml');
GO

Data Types for Bulk Exporting or Importing SQLXML Documents

To bulk export or import SQLXML data, use one of the following data types in your format file:

Data type	Effect
SQLCHAR or SQLVARCHAR	The data is sent in the client code page or in the code page implied by the collation). The effect is the same as specifying the DATAFILETYPE = 'char' without specifying a format file.
SQLNCHAR or SQLNVARCHAR	The data is sent as Unicode. The effect is the same as specifying the DATAFILETYPE = 'widechar' without specifying a format file.
SQLBINARY or SQLVARBIN	The data is sent without any conversion.

General Remarks

For a comparison of the BULK INSERT statement, the INSERT ... SELECT * FROM OPENROWSET(BULK...) statement, and the bcp command, see Bulk Import and Export of Data (SQL Server).

For information about preparing data for bulk import, see Prepare Data for Bulk Export or Import (SQL Server).

The BULK INSERT statement can be executed within a user-defined transaction to import data into a table or view. Optionally, to use multiple matches for bulk importing data, a transaction can specify the BATCHSIZE clause in the BULK INSERT statement. If a multiple-batch transaction is rolled back, every batch that the transaction has sent to SQL Server is rolled back.

Interoperability

Importing Data from a CSV file

Comma-separated value (CSV) files are not supported by SQL Server bulk-import operations. However, in some cases, a CSV file can be used as the data file for a bulk import of data into SQL Server. For information about the requirements for importing data from a CSV data file, see Prepare Data for Bulk Export or Import (SQL Server).

Logging Behavior

For information about when row-insert operations that are performed by bulk import are logged in the transaction log, see Prerequisites for Minimal Logging in Bulk Import.

Restrictions

When using a format file with BULK INSERT, you can specify up to 1024 fields only. This is same as the maximum number of columns allowed in a table. If you use BULK INSERT with a data file that contains more than 1024 fields, BULK INSERT generates the 4822 error. The bcp utility does not have this limitation, so for data files that contain more than 1024 fields, use the bcp command.

Performance Considerations

If the number of pages to be flushed in a single batch exceeds an internal threshold, a full scan of the buffer pool might occur to identify which pages to flush when the batch commits. This full scan can hurt bulk-import performance. A likely case of exceeding the internal threshold occurs when a large buffer pool is combined with a slow I/O subsystem. To avoid buffer overflows on large machines, either do not use the TABLOCK hint (which will remove the bulk optimizations) or use a smaller batch size (which preserves the bulk optimizations).

Because computers vary, we recommend that you test various batch sizes with your data load to find out what works best for you.

Security

Security Account Delegation (Impersonation)

If a user uses a SQL Server login, the security profile of the SQL Server process account is used. A login using SQL Server authentication cannot be authenticated outside of the Database Engine. Therefore, when a BULK INSERT command is initiated by a login using SQL Server authentication, the connection to the data is made using the security context of the SQL Server process account (the account used by the SQL Server Database Engine service). To successfully read the source data you must grant the account used by the SQL Server Database Engine, access to the source data. In contrast, if a SQL Server user logs on by using Windows Authentication, the user can read only those files that can be accessed by the user account, regardless of the security profile of the SQL Server process.

When executing the BULK INSERT statement by using sqlcmd or osql, from one computer, inserting data into SQL Server on a second computer, and specifying a data_file on third computer by using a UNC path, you may receive a 4861 error.

To resolve this error, use SQL Server Authentication and specify a SQL Server login that uses the security profile of the SQL Server process account, or configure Windows to enable security account delegation. For information about how to enable a user account to be trusted for delegation, see Windows Help.

For more information about this and other security considerations for using BULK INSERT, see Import Bulk Data by Using BULK INSERT or OPENROWSET(BULK...) (SQL Server).

Permissions

Requires INSERT and ADMINISTER BULK OPERATIONS permissions. Additionally, ALTER TABLE permission is required if one or more of the following is true:

Constraints exist and the CHECK_CONSTRAINTS option is not specified.

[!UWAGA]

Disabling constraints is the default behavior. To check constraints explicitly, use the CHECK_CONSTRAINTS option.
Triggers exist and the FIRE_TRIGGER option is not specified.

[!UWAGA]

By default, triggers are not fired. To fire triggers explicitly, use the FIRE_TRIGGER option.
You use the KEEPIDENTITY option to import identity value from data file.

Examples

A. Using pipes to import data from a file

The following example imports order detail information into the AdventureWorks.Sales.SalesOrderDetail table from the specified data file by using a pipe (|) as the field terminator and |\n as the row terminator.

BULK INSERT AdventureWorks2012.Sales.SalesOrderDetail
   FROM 'f:\orders\lineitem.tbl'
   WITH 
      (
         FIELDTERMINATOR =' |',
         ROWTERMINATOR =' |\n'
      );

B. Using the FIRE_TRIGGERS argument

The following example specifies the FIRE_TRIGGERS argument.

BULK INSERT AdventureWorks2012.Sales.SalesOrderDetail
   FROM 'f:\orders\lineitem.tbl'
   WITH
     (
        FIELDTERMINATOR =' |',
        ROWTERMINATOR = ':\n',
        FIRE_TRIGGERS
      );

C. Using line feed as a row terminator

The following example imports a file that uses the line feed as a row terminator such as a UNIX output:

DECLARE @bulk_cmd varchar(1000);
SET @bulk_cmd = 'BULK INSERT AdventureWorks2012.Sales.SalesOrderDetail
FROM ''<drive>:\<path>\<filename>'' 
WITH (ROWTERMINATOR = '''+CHAR(10)+''')';
EXEC(@bulk_cmd);