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mysqli::prepare
mysqli_prepare
Prepares an SQL statement for execution
Description
Object oriented style
publicmysqli_stmt|falsemysqli::prepare(stringquery);
Procedural style
mysqli_stmt|falsemysqli_prepare(mysqlimysql,
stringquery);
Prepares the SQL query, and returns a statement handle to be used for further operations on the statement. The query must consist of a single SQL statement.
The statement template can contain zero or more question mark (?
) parameter markers—also called placeholders. The parameter markers must be bound to application variables usingmysqli_stmt_bind_param
before executing the statement.
Parameters
-
link
-
Procedural style only: A link identifier returned by
mysqli_connect
ormysqli_init
-
query
-
The query, as a string. It must consist of a single SQL statement.
The SQL statement may contain zero or more parameter markers represented by question mark (
?
) characters at the appropriate positions.Note平方的标记只在某些地方是合法的L statements. For example, they are permitted in the
VALUES()
list of anINSERT
statement (to specify column values for a row), or in a comparison with a column in aWHERE
clause to specify a comparison value.However, they are not permitted for identifiers (such as table or column names), or to specify both operands of a binary operator such as the
=
equal sign. The latter restriction is necessary because it would be impossible to determine the parameter type. In general, parameters are legal only in Data Manipulation Language (DML) statements, and not in Data Definition Language (DDL) statements.
Return Values
mysqli_prepare
returns a statement object orfalse
if an error occurred.
Examples
Example 3.58mysqli::prepare
example
Object oriented style
prepare("SELECT District FROM City WHERE Name=?"); /* bind parameters for markers */ $stmt->bind_param("s", $city); /* execute query */ $stmt->execute(); /* bind result variables */ $stmt->bind_result($district); /* fetch value */ $stmt->fetch(); printf("%s is in district %s\n", $city, $district);
Procedural style
The above examples will output:
Amersfoort is in district Utrecht
See Also
mysqli_stmt_execute |
mysqli_stmt_fetch |
mysqli_stmt_bind_param |
mysqli_stmt_bind_result |
mysqli_stmt_get_result |
mysqli_stmt_close |