7.15.11. in_records — Groonga v10.1.1-31-g1e46ba6 documentation

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# 7.15.11. `in_records`

## 7.15.11.1. Summary

New in version 7.0.2.

You can use `in_records` for using an existing table as condition patterns. Each record in the existing table is treated as a condition pattern.

You may be able to reduce multiple queries to only one query by `in_records`.

`in_records` is similar to sub_filter. Here are differences of them:

> - `sub_filter` requires a reference column to condition table but `in_records` doesn’t require.

> - `sub_filter` requires an index column for the reference column but `in_records` doesn’t require.

> - `sub_filter` can use all logical operations but `in_records` can use only AND logical operation in one pattern.

> - `sub_filter` can use only the value of one reference column for condition but `in_records` can use one or more values for condition. You can use multiple columns, functions and so on for multiple values.

> - `sub_filter` uses index search but `in_records` uses sequential search.

## 7.15.11.2. Syntax

`in_records` has four or more parameters:

    in_records(condition_table,
               value1, mode1, condition_column_name1,
               ...,
               valueN, modeN, condition_column_nameN)

## 7.15.11.3. Usage

Here is a schema definition and sample data.

Sample schema:

Execution example:

    table_create Tags TABLE_PAT_KEY ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    table_create Conditions TABLE_PAT_KEY ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    column_create Conditions user_pattern COLUMN_SCALAR ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    column_create Conditions tag COLUMN_SCALAR Tags
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    column_create Conditions max_length COLUMN_SCALAR UInt32
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    table_create Memos TABLE_HASH_KEY ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    column_create Memos user COLUMN_SCALAR ShortText
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    column_create Memos tag COLUMN_SCALAR Tags
    # [[0, 1337566253.89858, 0.000355720520019531], true]

Sample data:

Execution example:

    load --table Memos
    [
    {"_key": "Groonga is fast",          "user": "alice", "tag": "groonga"},
    {"_key": "Mroonga is fast",          "user": "alice", "tag": "mroonga"},
    {"_key": "Groonga is very good!",    "user": "alice", "tag": "groonga"},
    {"_key": "Droonga is fast",          "user": "david", "tag": "droonga"},
    {"_key": "Groonga is a HTTP server", "user": "david", "tag": "groonga"}
    ]
    # [[0, 1337566253.89858, 0.000355720520019531], 5]

Sample conditions:

Execution example:

    load --table Conditions
    [
    {"_key": "lic + groonga", "user_pattern": "lic", "tag": "groonga", max_length: 20},
    {"_key": "dav + droonga", "user_pattern": "dav", "tag": "droonga", max_length: 50}
    ]
    # [[0, 1337566253.89858, 0.000355720520019531], 2]

Here is a simple usage of `in_records` that searches by records in `Conditions` table. Each record is used as a condition:

Execution example:

    plugin_register functions/string
    # [[0, 1337566253.89858, 0.000355720520019531], true]
    select \
      --table Memos \
      --filter 'in_records(Conditions, \
                           user,                 "@", "user_pattern", \
                           tag,                 "==", "tag", \
                           string_length(_key), "<=", "max_length")' \
      --sort_by _id \
      --output_columns _key,user,tag
    # [
    #   [
    #     0,
    #     1337566253.89858,
    #     0.000355720520019531
    #   ],
    #   [
    #     [
    #       [
    #         2
    #       ],
    #       [
    #         [
    #           "_key",
    #           "ShortText"
    #         ],
    #         [
    #           "user",
    #           "ShortText"
    #         ],
    #         [
    #           "tag",
    #           "Tags"
    #         ]
    #       ],
    #       [
    #         "Groonga is fast",
    #         "alice",
    #         "groonga"
    #       ],
    #       [
    #         "Droonga is fast",
    #         "david",
    #         "droonga"
    #       ]
    #     ]
    #   ]
    # ]

The `filter` tries the following three conditions for each record:

> - `Memos.user` matches (`@`) `Conditions.user_pattern`.

> - `Memos.tag` equals (`==`) `Conditions.tag`.

> - The number of characters in `Memos._key` is less than or equals to `Conditions.max_length`.

If at least one record in `Conditions` table returns true for the all three conditions, the record in `Memos` is matched.

The first record in `Conditions` table use the following conditions:

> - `Memos.user` has `"lic"` substring.

> - `Memos.tag` is `"groonga"`.

> - The number of characters in `Memos._key` is less than or equals to `20`.

This condition matches the following records:

> - `{"_key": "Groonga is fast", "user": "alice", "tag": "groonga"}`

The second record in `Conditions` table use the following conditions:

> - `Memos.user` has `"dav"` substring.

> - `Memos.tag` is `"droonga"`.

> - The number of characters in `Memos._key` is less than or equals to `50`.

This condition matches the following records:

> - `{"_key": "Droonga is fast", "user": "david", "tag": "droonga"}`

The result has the all above records.

## 7.15.11.4. Parameters

`in_records` requires four or more parameters.

### 7.15.11.4.1. Required parameters

`condition_table` and tuples of `value`, `mode_name` and `condition_column_name` are required. You can specify multiple tuples of `value`, `mode_name` and `condition_column_name`

#### 7.15.11.4.1.1. `condition_table`

Specifies a table that has conditions as its records.

### 7.15.11.4.2. `value`

Specifies a value to be compared.

### 7.15.11.4.3. `mode_name`

Specifies a mode name that specifies how to compare value with a value of condition_column_name.

See default_mode for available mode names. All mode names except `"NEAR"`, `"SIMILAR"` and `"SUFFIX"` are supported.

### 7.15.11.4.4. `condition_column_name`

Specifies a column name of condition_table to be used as condition.

### 7.15.11.4.5. Optional parameter

There are no optional parameter.

## 7.15.11.5. Return value

`in_records` returns whether the record is matched one of records of the specified condition table or not.

If the record is matched, it returns `true`. Otherwise, it returns `false`.