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author | Andrey Andreev <narf@devilix.net> | 2018-01-13 12:57:11 +0100 |
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committer | Andrey Andreev <narf@devilix.net> | 2018-01-13 12:57:11 +0100 |
commit | 02a0518e1c56ba3506f370362ac5ebdb8a138312 (patch) | |
tree | 8b4684192b403dcae17d298eb4fc9e7ab001acad /user_guide_src/source/database/metadata.rst | |
parent | f0b9735d5857e6c07c8f5824b13cff4828db3cfe (diff) |
[ci skip] 3.1.7 release
Diffstat (limited to 'user_guide_src/source/database/metadata.rst')
-rw-r--r-- | user_guide_src/source/database/metadata.rst | 130 |
1 files changed, 0 insertions, 130 deletions
diff --git a/user_guide_src/source/database/metadata.rst b/user_guide_src/source/database/metadata.rst deleted file mode 100644 index b8be809b6..000000000 --- a/user_guide_src/source/database/metadata.rst +++ /dev/null @@ -1,130 +0,0 @@ -################# -Database Metadata -################# - -************** -Table MetaData -************** - -These functions let you fetch table information. - -List the Tables in Your Database -================================ - -**$this->db->list_tables();** - -Returns an array containing the names of all the tables in the database -you are currently connected to. Example:: - - $tables = $this->db->list_tables(); - - foreach ($tables as $table) - { - echo $table; - } - - -Determine If a Table Exists -=========================== - -**$this->db->table_exists();** - -Sometimes it's helpful to know whether a particular table exists before -running an operation on it. Returns a boolean TRUE/FALSE. Usage example:: - - if ($this->db->table_exists('table_name')) - { - // some code... - } - -.. note:: Replace *table_name* with the name of the table you are looking for. - - -************** -Field MetaData -************** - -List the Fields in a Table -========================== - -**$this->db->list_fields()** - -Returns an array containing the field names. This query can be called -two ways: - -1. You can supply the table name and call it from the $this->db-> -object:: - - $fields = $this->db->list_fields('table_name'); - - foreach ($fields as $field) - { - echo $field; - } - -2. You can gather the field names associated with any query you run by -calling the function from your query result object:: - - $query = $this->db->query('SELECT * FROM some_table'); - - foreach ($query->list_fields() as $field) - { - echo $field; - } - - -Determine If a Field is Present in a Table -========================================== - -**$this->db->field_exists()** - -Sometimes it's helpful to know whether a particular field exists before -performing an action. Returns a boolean TRUE/FALSE. Usage example:: - - if ($this->db->field_exists('field_name', 'table_name')) - { - // some code... - } - -.. note:: Replace *field_name* with the name of the column you are looking - for, and replace *table_name* with the name of the table you are - looking for. - - -Retrieve Field Metadata -======================= - -**$this->db->field_data()** - -Returns an array of objects containing field information. - -Sometimes it's helpful to gather the field names or other metadata, like -the column type, max length, etc. - -.. note:: Not all databases provide meta-data. - -Usage example:: - - $fields = $this->db->field_data('table_name'); - - foreach ($fields as $field) - { - echo $field->name; - echo $field->type; - echo $field->max_length; - echo $field->primary_key; - } - -If you have run a query already you can use the result object instead of -supplying the table name:: - - $query = $this->db->query("YOUR QUERY"); - $fields = $query->field_data(); - -The following data is available from this function if supported by your -database: - -- name - column name -- max_length - maximum length of the column -- primary_key - 1 if the column is a primary key -- type - the type of the column |