The NLP++ functions for interfacing with a database are listed here in table form for easy reference. For examples of these functions, refer to the individual function pages included in the Database Functions section. Also available is a sample analyzer illustrating connection to a database, in Samples\database1. An introductory page is available at Database1 Analyzer.
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FUNCTION NAME |
RETURNS |
DESCRIPTION |
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dballocstmt() |
BOOL |
Create a handle for an active database statement. (Stored internally, allows only one active handle at a time.) |
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dbbindcol(column_num, type_str, size_str, &var, &flag_var) |
BOOL |
Bind the given database column number to the NLP++ variable var. type_str specifies the database data type being fetched. size_str specifies the size needed to store the database value being retrieved -- for some types, it is ignored. flag_var is a second NLP++ variable used to flag whether the currently fetched row contains a value in the column being fetched. Calls to dbbindcol are followed by calls to dbfetch in order to fetch successive database rows. Note that the ampersands are needed to indicate call by reference, i.e., that values are being passed up to the two NLP++ variables. E.g., dbbindcol(1,"string",255, &G("employee name"),&G("result flag")); |
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dbclose() |
BOOL |
Close the currently open database. (Only one database can be open at a time.) |
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dbexec(cmd_str) |
BOOL |
Send a statement to the currently open database. A modular function that creates a statement handle, sends the command string, then closes the statement handle. |
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dbexecstmt(cmd_str) |
BOOL |
Send a statement using the currently open statement handle. Assumes a statement has been opened with dballocstmt. |
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dbfetch() |
BOOL |
Fetch a row from a database. Columns bound by previous calls to dbbindcol will get their variables filled with values from the columns in this database row. Returns 1 as long as rows successfully fetched, else 0. |
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dbfreestmt() |
BOOL |
Frees the statement handle allocated by dballocstmt. Only one statement handle can be active at a time. |
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dbopen(db_str [, user_str] [, password_str]) |
BOOL |
Open the given database name with user name and password. Depending on the database and account set up, the user name and password may be optional. |
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