- Overview
- Main remarks
- Required versions
- Using WLanguage commands in SQL queries
- Limitations of MySQL version 3.23x
- Managing large files
- INSERT queries and automatic identifier
- Creating a table with HCreation
- Support for Unicode
- Connection with SSL certificates
- Main specific features
- Locking records
- Identical records
- Transactions
- SET or ENUM items
- xBlob items
- Array items
- Using INSERT/UPDATE queries to insert text into a LONGBLOB item (binary memo) on MySQL
- Partial indexing of memos and full-text indexing
- Specific features regarding HFSQL functions and SQL functions
Native MySQL Connector: Specific features and remarks
 Available only with this kind of connection
The following paragraphs present the main aspects and specific features of the Native MySQL Connector. Caution: This version of the Native MySQL Connector operates with: - WINDEV 28 or WEBDEV 28.
- Client layer of MySQL (LibMySQL.DLL file):
- 32-bit client layer to use the 32-bit Native MySQL Connector (version 3.x to 5.x tested).
- 64-bit client layer to use the 64-bit Native MySQL Connector (version 5.x tested).
Using WLanguage commands in SQL queries WLanguage commands cannot be used in SQL queries. Limitations of MySQL version 3.23x The MySQL database version 3.23x does not support: - the Partial Fetch. The use of Partial Fetch with the SQL functions of WLanguage has the same effect as if no Partial Fetch was used.
- the Unions.
Managing large files When handling large files, all the records are loaded in memory. To reduce memory usage, it is recommended to: - use a filter (HFilter) before initializing a browse (HReadFirst / HReadLast, ...)
- use queries whose selection conditions are selective enough
- avoid performing searches.
INSERT queries and automatic identifier The automatic identifiers are not supported by the INSERT queries (created through programming or in the query editor). To use an automatic identifier, call HAdd on the table. Creating a table with HCreation Support for Unicode When Unicode is supported on the connection (default mode), the text items of the queries run with the hQueryWithoutCorrection constant are in Unicode format. If a Unicode string is assigned to an Ansi string, the conversion is automatically performed by WINDEV and WEBDEV by using the character set defined with ChangeCharset. If the connection is ANSI ("WD Unicode Support = 0" in the extended information specified by HDescribeConnection or HOpenConnection), the text items of the queries run with the hQueryWithoutCorrection constant are in ANSI format. Connection with SSL certificates To establish a connection with SSL certificate, you must: - Install a version of the MySQL server that supports the SSL connections. For more details, see the MySQL documentation.
- Create the necessary certificates.
- Establish a connection by using the following keywords in the advanced information of the connection :
| | | Keyword | Use |
|---|
| SSL Key | Path of key file. | | SSL Cert | Path of certificate file. | | SSL CA | Path of certification authority file. | | SSL CAPath | Path of the directory containing the certificates of the recognized SLL certification authorities, in PEM format. | | SSL Cipher | List of authorized ciphers. |
Example of SSL connection on the CRM database of the mysqlserver.domain.fr server:
MyConnection is Connection
// Describe the connection
MyConnection.User = "root"
MyConnection.Password = "secret"
MyConnection.Server = "mysqlserver.domain.fr"
MyConnection.Database = "CRM"
MyConnection.Provider = hNativeAccessMySQL
MyConnection.Access = hOReadWrite
// Describe the extended information for an SSL connection
MyConnection.ExtendedInfo = [
SSL KEY = E:\MySSLCertificates\mysql.key;
SSL CERT = E:\MySSLCertificates\mysql_cert.pem;
SSL CA = E:\MySSLCertificates\ca-cert.pem;
SSL CAPATH = E:\MySSLCertificates\CA\
]
// Open the connection
HOpenConnection(MyConnection)
Remark: These parameters correspond to the parameters of the mysql_ssl_set function of the C API for accessing MySQL. Locking records The lock options (hLockWrite and hLockReadWrite constants) that can be used with HFSQL functions are not supported in this version. Identical records The Native MySQL Connector cannot differentiate between two identical records (two records with identical values for all the items, excluding memo items). When a record is modified or deleted, all the identical records will be modified or deleted. Transactions To manage the transactions, you must use a type of MySQL table that supports the BEGIN, COMMIT and ROLLBACK commands. SET or ENUM items The SET and ENUM items are automatically processed and imported as text memo in WINDEV and WEBDEV. Indeed, the SET and ENUM items have no equivalence in HFSQL. They contain numeric values (indices) that correspond to "text" values. These are the "text" values that are imported. xBlob items The xBlob items in MySQL are automatically processed and imported as text memo in WINDEV or WEBDEV: - the BLOB items are imported as binary memo items.
- the LONGTEXT items are imported as text memo items.
Array items The array items are not supported by the Native Connector. If you are using an array item, only the value of index 1 in the array will be handled by HFSQL functions (read/write). Using INSERT/UPDATE queries to insert text into a LONGBLOB item (binary memo) on MySQL To allow the management of Unicode items, the connections of the Native MySQL Connector are opened in UTF8: all the requests and the data are exchanged in UTF8 with the server. The server converts the request and the values into the charset corresponding to each column, except for a LONGBLOB item (binary memo): in this case, the value is inserted as it is. For a LONGBLOB item: - if the connection is in ANSI format, the inserted text value is in ANSI format.
- if the connection is in UTF8 format, the inserted text value is in UTF8 format; in this case, a compatibility problem may occur.
To avoid this conversion problem in UTF8, you can: Partial indexing of memos and full-text indexing The partial indexing of memos as well as the full-text indexing are not taken into account: - when importing MySQL tables into the analysis.
- when HCreation is used.
If these features are defined in the analysis, they will be taken into account when running the SQL queries (with the hQueryWithoutCorrection constant) that use the SQL "CREATE TABLE" and "MATCH AGAINST" functions. Specific features regarding HFSQL functions and SQL functions The specific features for using the HFSQL and SQL functions with the Native MySQL Connector are as follows: | | | Limitations | Affected functions |
|---|
Multi-file query (join): - HAdd, HModify and HDelete are not supported.
- Table control based on a multi-file query (join): HAdd, HModify and HDelete are not supported.
| HAdd
HModify
HDelete | The searches performed on some complex queries with HReadSeek* may fail in this version.
This problem will be fixed in a forthcoming version. | HReadSeek, HReadSeekFirst, HReadSeekLast | When using the Native MySQL Connector, you must specify the "DataBase" used.
If you are using HConnect, the "DataBase" must be specified in the additional information as follows:
"initial catalog = DataBaseName" | HConnect | When creating tables with HCreation, the table names must contain no accented character (Example: "ÉlanFile").
This is a problem specific to MySQL (tested on versions 3.23.52-max-nt and 3.23.47-max-nt of the MySQL server). Running the SQL "DROP TABLE" command, performed by HCreation to delete the table if it already exists, may cause the MySQL server to stop unexpectedly.
For more details, see Native MySQL Connector: Specific features. | HCreation |
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